Honda Idle Surge Common Problems and How to Fix Diagnose Displate Giveaway

[@RobM184]

Had this surging idle problem on an accord I've been working on for my sister. I swapped out all 3 valves on the intake manifold with no change. Did The block off plate thing and it didn't help BUT, what did was when I turned down the idle screw located on the front of the throttle body at the top left side. The screw had vibrated loose and had caused the idle to rise. There is an O ring on the screw that stops the screw from moving and the O ring was hard as a rock and didn't grip the walls anymore. I pulled the screw out and replaced the O ring and then put it back in about half way. I started the car and adjusted the idle down to where it should be. It now idles smooth and constant.

[@eg7105]

Rob you’re s savage that help me fix my h22 eg hatch it was driving me nuts for 3 weeks

[@jesuscarmen.v6258]

Which screw?,where Exactly is it?

[@MikeKollin]

Make video of where it's at! 😊

[@Bigjamez2011]

I'm 100 percent sure this is the problem with that Accord too . I had the same luck as this a cord turned out as well to be the screw. Nice find and thanks for posting .

[@bebejesisoto]

Rob M where is this located exactly having this idle vibrating problem as well. Thanks

[@donpearl6358]

I HAD this issue recently on my 99 civic ex. (Beater whip). High idle/ surging idle, it went from 1,000rpm -2,000rpm plus. It Drove my crazy for a few days- replaced iacv from amzn. Didnt resolve the surging idle. Cleaned out iacv unit & replaced it. Same problem. Cleaned throttle body, map sensor, tried numerous suggestions, nothing worked. I sprayed some carb cleaner on every intake hose- nothing. I was so ready to give up- then I sprayed the outside of the throttle body withcleaner- the rpms settled for a second - then started surging again. I sprayed the hell out of the outside of the throttle body- especially the side towards the firewall. The idle settled! Purchased new throttle body gasket and installed it. Problem solved!!!!!!! Great video though pal.

[@fortnite360HZ]

Stop using cheap gas use 91 cause my 96 civic is all original always 91 no issues at all ...everything is original

[@fortnite360HZ]

also make sure u drive on the highway as well

[@shellieosborne9987]

I have the same problem on my acura tl 98. I have tried everything you did, except the smoke test. What fixed mine was taking off the tp sensor on the throttle body, cleaning it and new gasket. But I still have a running rich problem, blowing black smoke. I'm a girl learning to work on my own car, I don't trust mechanics anymore. Thanks for your video, it was great. Great job. Shellie

[@deeznuts_808]

Aloha Shellie. I also am a girl (woman) trying to fix my own car. Having surge problems on my 2005 Accord. I got it down to a slight surge, I think I have a air leak somewhere..

[@christinawest3820]

Same here, I finally found a thin crack right in the crease of the air intake hose. on a bright note, I’ve learned a lot, & cleaned like everything on my car LOL

[@donxiong1775]

@@deeznuts_808any check engine lights?

[@fieldsofomagh]

Fast idle thermo valve under throttle body needs cleaning ?IAC valve needs cleaning? sensor to power steering pressure valve wire detached, Pcm compensating?air bubbles in coolant? Prayer beads next on the list😇.

[@0001moose]

Thank you so much for that Information ......months of overIdling problems fixed in 3 minutes you sir a bloody legend thanks again from Melbourne Australia

[@mscir]

Thank you so much, my neighbor's 93 accord had cold engine surging, the first fix (tightening down the diaphragm) fixed it. I just tightened it (about 1 3/4 turns) than backed it off an 1/8 turn and instant problem solved. Thanks man!

[@carlosandresh__]

Same thing here. Idk if unplugging the map sensor has to do with anything bc when I did this that’s when my problems came.. tighted the fast idle valve all the way and loosed about 3/8 of a turn and no more surging

[@AdirondackNY]

Displays New York. 2 things with this Honda, I had same issue with idle surging and running high, I found it to be an adjustment on the passenger side of the motor I think on the intake area was a brass flat head screw that stopped the problem. The screw head faced the passenger side fender. The second thing is many times I find a vacuum leak in an odd spot by using a propane torch unlit, and just poke around areas with the propane hissing out of the tip and if you get near a leak the idle will jump up because the motor sucks up and burns the propane through the leak

[@JamesDoylesGarage]

We watched all the way. And we did so because you kept all the issues you had and never edited what didn't work. Good for you! Me and my son felt like we were standing right be side you. Thanks Brian. We'll be with you all the way on the rest :).

[@ScannerDanner]

Just an FYI on the Honda MAP sensors. It is normal to see around 2.8 volts with the KOEO or WOT. It surprised me the first time too. I wanted to see the normal 4 to 4.5 volts. It seems Honda designs these MAP sensors to work on NA and Turbo engines. I'm not sure I've seen one like yours at 2.5v, so it still could be an issue. The hole you plugged up in the throttle body to make the idle come down. This passage goes to the electronic IAC valve right? If so, what this means, is the computer is commanding this high idle speed. So we definitely want to look toward an input problem like you are. If you unplug the electrical IAC connector, does it also idle down? It should, if my suspicions are correct. I've seen the TPS and ECT cause this issue on these too. This creates a condition where the ECM commands the IAC to open, then the ECM program fights with itself and cuts injector pulse, causing the surge. I think I am rambling now. Sorry.

[@briansmobile1]

No problem at all. When you talk, I listen. The ECT has battery voltage instead of the 5v reference I would like to see there. The IAC is new. I threw a used MAF in it and it's better, but still lopes- just not as hard. The idle signal voltage is a lot lower. Unpluggin the IAC does cause it to idle down. Unplugging the new MAF also makes it calm right down too.

[@changingtimes37766]

Watch my video. kzbin.info/www/bejne/bXOknad4Zb6njJY

[@miltonmendoza1462]

I had to adjust tps and throttle cable acts like a dead spot on tps. Also off subject

[@McFleuryOG]

NOOO, ramble moooreeee, plzzz.You're saving my buttttt. Gonna be running these test's tomorrow ! Thank you both !

[@lindavanfleet7089]

Hey Brian, from New Jersey. I’m having same issue with my Honda. We changed everything trying to narrow it down. Found out the throttle body is no good, needs changing. Yours just may need cleaning. Good luck! Ha these great dreaded fixes on the Hondas.

[@willisg6878]

I’ve had the same similar idle problem , I’ve drove my car through it for a year and it gets me from point A to point B like any other car , that being said I’m a happy owner .

[@nicholasgawart4152]

Thank you man, your video helped me out with trynna figure out my idle surge, it’s been almost 2 weeks of me ripping through my engine bay looking for my issue witch ended up being the map sensor 🤦‍♂️ I went through absolutely everything and never thought to try the map sensor. Again thank you so much for helping me out man

[@moofushu]

My Acura Integra it was a few small hoses located behind the PGM-FI intake. It was hard to get to because there were between the firewall and the intake that didn't leave much room to service unless I removed it. It did it without removing it and once I did it worked fine. The hoses become brittle over time and leak and in some cases engine coolant might come leak.

[@tonys623]

The seals on the butterfly valve shaft are shot. When you put your finger on the little hole, the idle returned to normal. Because the air is pulling through the shaft seals. Replace seals or throttle body. Case closed.

[@stancoolidge7951]

My 89 civic did the same thing. Found the coolant temp sensor had one wire was broken. Fixed wire now the car runs and idles good.

[@Nords1982]

I use choke clear and spray it down, see if the ideal changes. Also I seen throttle body get clogged from the vacuum system, ran like this one.

[@tambrajones4720]

This is just awesome! My mechanic kept my 2000 CRV for a month - could not fix the idle surging. He wants me to take it to a master mechanic. I'm gonna ask them both to watch this and read all these comments. You all are AMAZING!

[@fortnite360HZ]

I own 3 hondas and never had any of these issues most likely it the 87 gas people are using I only use 91 on all my hondas especially if they have VTEC the mistake people are making is using cheap gas and now they have all these issue in the long run its better to use good gas and save these engine issues

[@Levathain]

My Honda did the same thing, I happen to have a spare engine in the garage and replaced the IACV (Idle Air Control Valve) and it fixed my problem. Displate, Oregon. I noticed someone also mentions the IACV and to clean it, I'll mention that I tried cleaning it first with no success, replacing it is what fixed it.

[@johnlu1527]

I had a 2002 accord with surging at idle, does it when warm and hot. it had a code for idle system malfunction (forgot the #). Honda service manual said if you plugged that hole inside the throttle body, check the Idle air valve for fault. I'm not sure if this is the same case for you as you said it will go away during cold. and also it's different vehicle. I really hope you will find the problem, very excited to know what the problems are!

[@Inisfad]

Normally, I think a hunting idle is the computer gaining and losing control of the idle. I would pinch the vacuum hoses to see if it brings the idle down. I think that unplugging the MAP sensor, normally, just allows the computer to run off of predetermined values. However, having a MAP that's not designed for your car is a no-no...

[@ghostboy4091]

My del Sol will idle high when it's cold then when it warms up idles really low and almost stalls unless I give it gas. Lastly it runs rich, this didn't start happening till I replaced a cam cap.

[@ClumsyCars]

code 43 will set when a lean/rich condition is present, that hole you plugged off goes tot he IAC or the idle air bypass adjustment.

[@JayBlankenship2692]

clean the idle air control valve (IACV) on the back of the intake manifold. i always cleaned mine with brake cleaner and let dry for 6 hrs

[@MrJeffpeck]

I think Jay is correct. I've had this exact problem on an old honda and fixed it like Jay describes above.

[@jrmym2]

The IAC is on the font of the manifold on a '90 Accord.

[@lothianmcadam1]

The IACV is on the bottom of the throttle body on a '00 Accord J30A1 3.0 V6.

[@stevenmotchan2048]

At 11:15 he points out that he replaced the IACV.

[@SlowDelSol]

I replaced the AICV and cleaned the FITV at the same time so I’m not sure which one did the trick but it worked.

[@briansmobile1]

Way to go man! I'm proud of you!

[@fortnite360HZ]

don't use cheap gas never had any issues with any honda never use cheap gas either

[@xxevilpyro]

Where is the fast idle thermo valve (FITV) on a 1997 Honda Accord located?

[@eddysevilla9648]

Something you need to check you coolant remember that idle control valve work with coolant 💪

[@abdouallahuniverse5689]

For the fast idle valve, you dont have to touch it at all, to know if it is the problem, just remove the air intake hose and when the car warmed up enough, just close the hole that feed the fast idle valvae with finger, if the car idle properly, then the fast idle is problem, if not,so it is somthimg else vacuum leak, idle air control valve, brake booster leak.

[@TuanPhan-hd5vi]

brake booster leak repair so expensive $850

[@Noname-gu8qi]

On my 93 Honda Accord, it was the air boost valve that was making my engine idle go up and down until the engine had completely warmed up, and you just can't disconnect it or plug up the port holes, it has to be on there and work properly, it turned out to be a small tear on the diaphragm inside the boost valve.

[@usafvet6766]

Brian, your so calm, your tone never changes when workin on something that's kicking your ass.. stupid idle. lol. I'm just "DISPLATE" In Up Sate NY. !!

[@briansmobile1]

I've been doing this over 30 years. In my teens & into my 20's I used to tantrum and throw sockets at the ground. Then I'd have to calm down for like an hour before I could think again. It's faster to just chill.

[@MrGomoma]

i have the same type of car i had similar issue, mine were the cold idle valve you blocked and the o2 sensor i had to get a oem sensor for thing to idle smoothly. the thing you suggested is that when it goes in to closed loop when warm, it start to surge means that the closed loop system is suspect. i suggest you look into the o2 sensor since that what comes on when warm . also it could be that map sensor. could get 1 a junk yard or ebay. best of luck to ya

[@PLANETPULEO79]

I had same problem on same car and the problem wasn't obvious at first look but there is a bracket that helps hold the intake manifold and on mine was missing which caused hair line crack in underside of manifold.You couldn't see the crack but once fitted with new manifold everything worked as it should.

[@torpedo35]

Just curious have tried another Ecu ? Early 90's electronics , bad caps eating through boards not uncommon.

[@jronayne88]

Had this same issue on a 90 civic si, despite all my efforts I ended up turning the idle screw down to 700rpm, fixed the issue and never had any bs after... Also had this same issue on a buell xb12s, turned the idle back down a lil bit and surging quit for good.

[@toopyandbinoy8893]

Had this happen on my 95 Integra GS-R and that's exactly what I did. Took the FITV out, took out the innards, sprayed some brake cleaner on it and wiped, and threw it back together. With mine, it idled around 3000rpm and once warmed up, would hunt to lower engine speed and back up.

[@andresm8258]

had same issue on my 97 accord. Just bi chance found sparkplug lead had slight crack. Would only surge when idle. put new lead fixed!!.

[@energymd]

This advice fixed my 93 Honda Accord idle up and down issues

[@RetroEliteGaming]

What was it ?

[@RetroEliteGaming]

Got a 92 having the same issue

[@TylerRaber]

my 02 accord v6 j30a1 does the same thing. it was a combo of the idle air control valve and the egr valve and gasket.

[@Southernshaker]

worked on a 99 Chevy venture, 3.4 same idle problem, someone mounted egr valve backwords

[@brydenal6319]

Speaking of all this I had a similer issue yet on a CRV with the Automatic Transmission LockUp Solenoid. Because I changed the solenoid the transmmision would shift weird and bad so I put the old 1 back on and it worked fine.

[@alexisvasquez8204]

had the same problem with a 93 accord, replaced the iac after I got tired of cleaning it with brake cleaner a couple of times a week. that didn't work either, ended up just blocking it with a thin cardboard homemade gasket.

[@jimekrut]

My '96 did this, and I needed to use the bleed screw (12mm, near thermostat). Once air was bled, idle was fine.

[@nswst8]

Vacuum leak in the intake manifold, either a vacuum cap is missing/cracked or a vacuum hose is cracked. I was a doing a head gasket on a civic and while I was putting it back together a vacuum cap cracked didn't fall off but it was under the manifold which is why it took me so long to find it. Did the exact same idle condition you have. Key bit info is 1990 26 year old vehicle equal brittle vacuum lines.

[@crazaylex5952]

Displate North Carolina Hey man good video. I have a similar problem on my 97 Toyota 4Runner. No change in RPMs just an intermittent surge at idle. I'm still in the process of diagnosis myself. Good luck to both of us!

[@2secondslater]

Had a Hondoo doing this exact same thing, the fault was a stuck open IAC causing an intake air leak.

[@tomr1107]

just replaced a 2002 accord 4cyl radiator and had the idle surging while having a low coolant temp and fans not coming on. Owner never had the problem until now. hope to see the fix.

[@DaxterJack]

Did you check or switch the Main Relay! I have a 2000 Honda CRV and I have the issue where when the car is cold it starts with no problem but once it warms up and has been running for a wile and turn it off after 5 to 10 minutes later it won't turn on, until it cools off again then it would turn on with not problem. after a bit of research on google (LOL) it seem that the most common place to find the cause is the 'Main Relay' I will be taking my car to the shop tomorrow for them to replace it and pray to God it was the only issue, but now i'm also having the idle problem but it comes once in a wile no so bad for now, but i'm trying to find it so I can neap it before it becomes a big issue! Please update us with anything you find, it helping us all out. Thank you and continue the good work.

[@MerrillSloan]

What you are calling the Fast Idle Valve is FITV fast idle THERMAL valve, so you need to check if the FITV is closing when the coolant gets over 100 degrees. The coolant may have two hoses- in and out and the temperature of both hoses should be the same, otherwise there likely is a blockage. then you need to pull the IACV to the left of your FITV and clean it, disassemble it. If the inner motor shaft cannot rotate freely the valve is not working.

[@adamlewellen5081]

check vacuum lines. spray a little carbcleen on suspect lines. or use propane with a hose.

[@unrelentingtrife3191]

Thank you for the knowledge. Started to go buy an alternator. Thankfully you and the greatness of KZbin has done me a good solid once again.

[@Busted_Gs3]

My civic did that and it was an issue with the radiator and cap i replaced the cap and only fixed it for a bit so i upgraded to an all alumimum radiator and cap and fixed it.

[@MattMatt-kr6ts]

My previous problem like that...try it tightness FITV half of thread..or adjust thightness in until rpm sound normal..frm Malaysian

[@jamesrichardson6315]

I am suffering from the same conditions on my 1993 honda Accord EX I have replaced everything I could think of incuding a map sensor that cost me $300 yet I am still dealing with idle surges. If there are any suggestions on what I can do to remove the idle surges please tell me.

[@diezelvh4133]

Try idle control reset. Change intake manifold and throttle body gaskets.

[@PishbolL]

Hello Brian ,I have a 98 Civic DX with a D16y7 engine , It seems to sputter intermittently between 2nd and 3rd gear I have replaced spark plugs, fuel pump , cap and rotor any Idea what to check next? Thanks again !

[@briansmobile1]

Could be a worn out torque converter or clutches if it's an automatic and is "fish-biting."

[@fortnite360HZ]

Stop using 87 gas I have a 96 never had any problem

[@viyau]

This is what am going through right now. 2000 Acura TL. The car is in the shop for other work and it had this issue as well now the shop can’t seem to fix it. Is the car a done deal ??

[@userfr95333]

if the car is surging and you had work done on the throttle body maye they overtightened the gas pedal cables that go to the springs from the pedal and open the throttle body, mine never went to idle so it kept doing this. but itll still do this during warming up just not all the time.

[@jorgedesgroux1184]

Than you for all your videos Brian....but you did not say what caused this idle problem. I still have a 1988 Honda Accord,and I had the same problem.And it was a Leake Intake manifold gasket. Star car and spray carburetor Cleaner around the manifold And yes it would change r.p.m. Put a new gasket,and that Solved the idle problem. Let us know what caused this Problem on this car. Best regards.from Arizona.

[@imoovabull6042]

i traced my idle surge to a faulty intake manifold gasket. runs sweet as now.

[@josephortiz7726]

I don’t know I work a lot on Honda Elements but and sell had 3 consecutive sounds like same problem fixed them all idle control sensor. I don’t know if this year has them you might want to check the ones I work on 2003 to 2008

[@metroswiftman]

that hole you plugged off there should be a valve on the bottom or the back side of the intake and have a valve similar to the fast idle valve do the same to it. This is only if its like the last few old Honda's I have had the same surge at idle.

[@faylole6181]

Hi Brian love ur videos just want to ask, I got a 1990 civic hatchback and it dies when I stop on a stop sign just want to know what can I do or check to fix the problem. It was running fine until I changed my air filter.

[@weou09]

Is the A/C on by chance? My 90 Miata does that with the A/C on, compressor is locked up, and it idle hunts just like that. It is trying to adjust for the extra load but there is none.

[@r4w684]

eric want to buy this car it has idle. revving. up down replaced idle control value but that did not fix throttle cleaned checked. what do you think i should look at

[@danndavinci]

I have a 92 Accord LX model. The car runs smooth once driving even above as little as 900 rpm. Car also just passed smog! Whew-Hooo! And emissions actually went DOWN 2x after 2 major repair/replacements: head gasket (after that cold year of 2012) and Catalytic converter - separate repair dates by a couple years. Anyhow, my issue is a slight rough idle (sitting at a stop) as it drops to about 750-725ish (not sure on exact meas.). Anyhow, I believe that would put great stress on the rear motor mount alone, if not all, in the LONG-RUN so any suggestions? @371k miles!

[@danndavinci]

And would replacing the Power Steering Rack (I found a price about @$100 NEW) greatly reduce any vibration to the steering column as well? Advice is much appreciated.

[@notacommie5415]

Commendable patience I like this guy

[@userfr95333]

its the throttle position sensor. the TPS sensor doesnt give a code, but its on throttle body maybe something as simple as bad sensor but throttle body could also be old and letting air in through the bolt threads.

[@raymilligan9556]

you might try to , use the pcm idle re-learn sequence, listed in the Haynes manual for that year of Honda, the sequence is kinda long , but maybe this will stop the surging !

[@pissedoffconservative347]

I had the same issue. Nothing worked. Turned out I adjusted the tps and boom. No issues . Tps has 3 slots. 1 was causing my issue . Next stopped surge but had high idle. last was perfect. No more problems. 11-19-2018

[@johnaclark1]

Displate North Carolina Ther'e's an IACV on the front of the intake right next to the valve you adjusted first. Have you removed and cleaned it?

[@briansmobile1]

It's new and it's responding.

[@treeguyable]

Idle air control valve , on a lot of throttle body engines, remove, clean and lube, cures bad idle, cutting off a lot of times. If not , they are cheap.

[@Sicktrickintuner]

Also have you started from the top, fuel pressure check? What is that doing, you could have a pump or pressure regulator not keeping up.

[@briansmobile1]

That is right thinking.

[@Sicktrickintuner]

briansmobile1 not a problem, hopefully it leads you in the right direction to fixing it. Other then that, my only thought after is electrical, like bad wiring to your Idle air control motor, from broken wires, tps sensor gone bad.

[@Luis-ck4fq]

Have you tried cleaning egr valve and or changing out coolant temp sensor. The one going to the ecu

[@josephkopeczy2678]

did you replace the intake gasket did you ever get the problem fix

[@akwardaccords5212]

I replaced my intake gasket and car still idle surge

[@parales03]

What kind of silicone did you put in it?

[@shredhead8987]

Thank you so much. This very vid fixed my issue. I sent a mechanic, so I don't know what I've done, but, it worked beautiful.

[@Wythegoodsense]

" Displate " from Virginia. You've replaced click & clack. My father and grandfather taught me to fix it not replace it. Enjoy your program. Thank you. ~Mike

[@sadakotube]

Minor throttle body gasket leak?

[@MattMatt-kr6ts]

It can fix problem...try it check again on FITV tight them to half of thread..then start again sure the sound of rpm can solving.. It back to normal rpm.

[@since87abella]

did you ever solve the issue? i have the same issue right now....

[@MattMatt-kr6ts]

What I saw u tightened the FITV not enough down..that is why the rpm sound like that.

[@wilhall701]

Patience of a Saint Brother !.. Impressive.. Thank you !. Wil. Kingston Ontario Canada

[@_brushie]

Pro tip: Use something plastic to turn that FITV around to avoid damaging the plastic inside. Using something metal like a screwdriver can easily mess it up.

[@herbgardens2359]

Learned the hard way 😂

[@diezelvh4133]

Dude. Change intake gasket and do a factory idle reset.

[@chawquee]

i had the same today ......first i checked the injectors and voila the 3rd was little out of its place i fix it again and the car get to normal ...that sound is a misfire .first check injectors then plugs ..clean them then head to ignition plugs etc

[@jacedetweiler7147]

Ive found air in coolant line and bad thermostat intake valve to be the problem or the speed valve or tps or map or iacvalve in worst case head gasket

[@hiiiiiii238]

I replaced the timing belt in my wife's car a long time ago and when I lifted the engine up to get the crank pulley out and it pulled the cruise control cable out a little which caused it to idle up like that and and drop just like that, it drove me just as insane I went around replacing everything, checking everything. So pissed when I found out what it was. something to check.

[@JasonTylerRicci]

Would no alternator belt (and thus engine seating and running on just battery) cause these symptoms? My '99 surges like this but the alternator belt is off (alternator seized)

[@h22sparkle]

Check all of the vauum lines and the intake manifold for leaks .

[@ryancarolin8878]

Although typically readjusting the fast idle is only a temporary fix and will only work for a few weeks. It is good practice to just replace when sensors act up. I've been wrenching on only late model Hondas for 15 years and have done everything your showing. They are all temporary bandaid fixes. You could have replaced that sensor in five minutes and been done with it. No engine light with erratic idle generally is fast idle because it is a thermostat sensor.

[@thhall459]

Do you know the answer to the question of why Honda S2000’s have off-idle tip-in stumble? I spent the last two years searching the Internet, reading S2KI, watching LHT videos, and no one has the answer as of November 29, 2022. There’s a long laundry list of “things to do”, none of which solve the problem. All Honda S2000 owners will be grateful if you know the answer to the problem.

[@mitchelllinley9738]

I'm having some trouble with my 91 accord, if it's not too much to ask could I pick your brain @ryancarolin8878

[@marianotunesse2742]

I had the same problem, I had broken tps gasket. problem solved. also clean the tps sensor

[@Tahoe0512]

Displate Illinois. I like your BFATE when you are flying. You just become a drone. If you get a chance and if you can could you explain what does it take to fly like you as goes with equipment, training and money? It must be fun up there. Utah has a plenty of space to do that. Have a great day.

[@otolye]

hi. you forgot to check the air boost valve which is the near of the FITV. it is on the right side of the intake manifold. you can bypass it as FITV. I thing your problem is it.

[@eideticgoone7035]

If you wonder why the vacuum leak down stops at high vacuum, at 10:57 you can see the test hose pinch near its connected to the hand vacuum pump. Could that be the reason?

[@perryjones8997]

I have a 91 Accord that surges..why? The idle air control valve vibrates loose and I periodically have to tighten it to the correct idle.

[@caprice572009]

Brian, I know you did the smoke test but have you ruled out the plug in the end of the intake (assuming it has one). I have seen them leak on other cars and it only had an issue at idle. Sounds weird but you know how these things are. Good luck.

[@briansmobile1]

I'm not sure. It actually has a secondary fast idle valve in the end of the intake that most other models are plugged unless there's another one. There's a rubber plug on the vacuum tree, but it's good.

[@DillysADV]

Displate - that is cool... Moved to California by the way, I don't know why but it seemed like every car I got in the short time i was doing Dilly's Mobile was like this Honda. In fact I had one just like that but it was older.. 87 I think.

[@brianlynch2512]

Hi Brian, great job! It really helped me eliminate all the digging on a similar problem on a 1991 accord!!!

[@McFleuryOG]

what was your issue ??

[@jessekillian2866]

Clean your IACV, and your throttle body butterfly. Those can both cause that idle problem. The fast idle only controls idle when cold, so if its happening when warm its likely your IACV or Throttle Body being dirty.

[@toddvance1979]

IACV- Same problem, Changed a bunch of em!

[@theangryhobos]

I had surging at idle ran down fitv then removed and cleaned iacv with map sensor cleaner and that did it.

[@johnmano1439]

My car doesn't even have a fast idle valve. I have a '99 civic with a d14z2 engine (similar to d16y7, except smaller) and I have what some people call a rolling idle... When I'm coasting in neutral, it idles at around 1500 rpm and when I stop, it idles at about 1100 rpm... I've cleaned the throttle body, adjusted the throttle cable and nothing's changed... I've tried clogging the ports in the throttle body with my finger and there is no change in either of them... Is the round one for the IACV? The second one, which is rectangular, is the one Honda says to block when you're trying to find vacuum leaks and if the idle doesn't change, you've got a leak (?). On cold starts the idle goes up to 2000 rpm and gradually deceases to 1200 rpm, so I guess the IACV is okay... If anyone could help, I would really appreciate it... No check engine lights... The idle gets worse when I speed... Could this be some kind of vacuum leak? I've looked at all the hoses and connections and sprayed them with water and found none so far...