Honda-Acura Surging Idle Speed (case study)

[@dannyr3346]

8 years later and this is still the Go to video for all service techs dealing with old ass Honda's.. Truly a testament to scanner Danners knowledge and his journey to the answers.

[@unionpride525]

as soon as you figured out the the cold-fast idle valve was open and you could thread it in I was yelling at my screen saying, "YES! YES! That;s it dude!!" that issue was killing me and I went and did the exact same thing you did! right on brother. thanks for your videos

[@EartAlienEB1]

You are a real Pro ! Many "mechanics" these days make fixing cars really troublesome...Thank God for guys like you that are real Pro's and allso are generous with us help seekers and post issue fix videos on KZbin . God Bless you and Hello from Romania in 2019. I have same issue with 2002 Toyota Yaris 1.0 4cyl vvti engine . will check tomorrow about this control valve.

[@geronimoveneracion8057]

Brother. Hands down, the best and amazingly detailed video on idle (fast idle valve) problems out of the dozens of videos I've come across. Never stop posting these vids man!

[@ScannerDanner]

Glad it helped!

[@jarinwilson9539]

One thing that always bothered me on older Hondas is that the TPS is riveted to the throttle body....slightly annoying And yeah, I've ran into this exact scenario a couple of times. Another awesome video Paul

[@roadworthy6901]

You can actually hear it without undoing a bolt, especially with aftermarket air intakes, sounds like a massive vacuum leak! Great video, this should be shared on all those awesome Honda forums.

[@cloudcloud1204]

This fix worked for me. Turned out my diaphragm was backed almost completely out in the valve. Was difficult to screw in. Used a quarter instead of a flat head. Worked great

[@ScannerDanner]

sweet! thanks for watching and commenting

[@catabaticanabatic3800]

Just bought a second-hand Honda and it had exactly this problem. Thanks for the video it has enabled a fix.

[@mr.nobody4900]

Thank you, Mr. Danner, for making this video it came to a huge help to me just yesterday dealing with excessive idle problems with my Honda after adjusting the fast idle valve the idle problem has gone away completely. Thank you.

[@ScannerDanner]

an honestly, the other HUGE problem in my field is most "professional mechanics" are parts changers and cannot do proper troubleshooting

[@tmanda323]

In my country the bigest problem is a lack of knowledge, a lack of information, without desire for learning....that's why most of professional mechanics are part changers

[@ScannerDanner]

@@tmanda323 where are you from my friend?

[@tmanda323]

@@ScannerDanner Serbia. Europe. I have your e book.

[@ScannerDanner]

@@tmanda323 Thank you! Armed with that, you can be one of the ones in your country to change things!

[@MarioHernandez-xp6vp]

I'm a part changer but just bc I don't want to go to a mechanic. Changed ny MAP sensor. And my TBS. Now I'm here to see a professional at work.

[@EKLEKTE_KURIA1]

Also make sure to check your throttle body gasket as well! They will break overtime and cause it to have a vacuum leak

[@michaelbarlow6062]

I think you were the first one to figure out to adjust that valve all the way down👍👍

[@ScannerDanner]

no problem at all my friend. it is still up for debate as to why this method of control is used, but at least we know for sure now what is causing the surging.

[@jHuff-dm7lz]

Hello ScannerDanner, I just went through the new Section 20 of the E-Book (Engine Performance Diagnostics) Cover to cover and man, I think you nailed it. If anyone has an idle performance issue with an engine, you got the answers. I had an 05 Doge 5.7 Durango with an intermittant stall--NO ONE-- could find the fix. I did. My Friends love it when I read your books.

[@TheChristofear]

Have the same surging issue but on a Mazda B2200 1993. Pretty much did what you did here except you can adjust the IACV without taking anything apart by just adjusting a screw on the outside, it runs so much smoother now. I have been trying to fix this surging issue for almost a month now and my next step was a new IACV which runs between $300-$500 new. Thanks for the video!

[@ScannerDanner]

good thought. I would say no on the coast comment. Decel fuel cut-off is a function caused by a rapid closing of the TPS along with a high RPM. So with no TPS activity, I don't see this being the issue. Of course, the main point which we can all agree on is the surge is being caused by injector shut down

[@ScannerDanner]

For sure man, and I truly value your input on this. I am still not convinced that this seat didn't work its way loose on this one, but not sure if I will know for sure until I see more of them. And this is a dying system, so I don't expect too many more. For anyone else reading this, be careful with this "fix" and please understand the variables here.

[@ScannerDanner]

a vacuum leak on a speed density engine (MAP engine) generally will not cause a lean condition (at least smaller leaks anyway). the reason is the MAP sensors "sees" the manifold psi increase and sends an increasing load signal to the PCM, the PCM in turn provides more fuel. So now you have more air and more fuel = RPM rise! The O2 is really not in play as part of the high idle here. It is a factor but no the main cause of more fuel being added.

[@gvvq-pi5ml]

Hi Paul, Eric the Car Guy had one of these valves on one of his videos, he screwed it right in then undone it about 1/4 turn and it cured hi..so think you done the right thing...I actually thought to start with when it surged it was slowing down and the IAV was opening it up to keep it running, but you proved it was the other way round..good work - Fred.

[@ScannerDanner]

Thanks for the tip. I think as long as the engine doesn't stall or give you any driveability issues when cold, then do we really care if the cold fast idle isn't to spec? As long as it is not too high of an RPM then I really don't care at all. If it is a paying customers car, let them know what you did and any future issues that the valve will need to be replaced. I still like the fix. Thanks again

[@Shmelkable]

Thank you so much for this video, I've tried everything to fix my idle problem, from the pcv to the iac and nothing worked. This video helped me and it was easy to understand. I was able to do it in an hour after watching your video. I appreciate it so much, you've earned another subscriber. Keep up the good work!

[@667NeighborOfBeast]

Thanks for this video, immediately solved my idle problem! I adjusted the valve to the max bottom and left it there. It's probably only temporary fix, but it will do the job until i buy new one.

[@angelramirez7747]

Scannerdanner you are 'THE MAN'! Me and my neighbor were diagnosing an idle issue on a 97 honda accord. After watching your video it took 5 minutes to determine the cold fast idle valve was the culprit and 20 minutes for the repair. Thanks for the great content scannerdanner!

[@ScannerDanner]

I like the comments and feedback! Keep them coming. I looks as though valve replacement would have been the proper fix hear. I will update this in a few months and let you guys know how our "fix" is doing, as this car is owned by one of our students.

[@indigo_dreamz]

Any updates please 🙏

[@ScannerDanner]

@piksylicious from 9 years ago but yes, this was a fix 😉

[@leeoshea2290]

@@ScannerDanner I have a 2004 honda jazz, in Australia. The IACV under and attached to the throttle body is water/coolant , magnetic, electronic (it plugs in), the spindle was seized hard. It took 3 days of soaking with carby cleaner, squirts of wd40 and ,eventually, a firm but gentle twist with pliers to start moving the spindle that appears to be magnetically controlled too, (what a pffft idea). So, the engine would idle fine at start up. Once warn/running temperature, the idle would fluctuate between 900 & 3,300. crazy. After repairing the IACV, the idle has been good for about 4 weeks. 1.5 l 5sp manual idle @ 750. well, yesterday the erratic idle restarted. With all the variables of possibilities it could be any of a dozen things. Think I'll start with cold idle valve adjustment. 2nd will be the IACV again (apparently if replacing, it has to be oem or the computer won't recognise it, what a pita). A new part here is over $900, about $550-$650 US depending on the day. Lots of 2nd hand refurbished? parts, don't trust those. It comes to a point when the parts to fix these cars are way more expensive than what the car is worth. It's a shame. When they run well, they are good cars. When they don't, well, bonfire night looks good. Thanks for the in depth analysis you have provided. Hopefully, at some point, this offset idle can be sorted for a reasonable cost. Mechanics here are way too expensive, as in, they want money even if they can't fix it. I don't mind paying labor costs, that's business, but, $1,000 or more for a non repair, supposedly diagnosing with no fix, I'll stick to you tube and try and try again until victory

[@timon2wheels355]

Thank you for this information. I have an Accord that has been do this since I got it. I purged cooling system, cleaned IAC but all it needed was the FITV adjustment!

[@ScannerDanner]

+tim browning sweet!

[@tlk8927]

My 1989 Honda Accord is surging like this. i'm going to try some of the things you show in this video.

[@ScannerDanner]

Good question my friend. RTN = return. SIG RTN = signal return, this is another name for a sensor ground. MAF RTN is MAF return. This is a unique design in that there are two grounds. One ground is the PCM MAF signal voltage sensing circuit and the other is a block ground. So the MAF grounds to the block and the PCM MAF sensing circuit grounds through the MAF sensor. (noise prevention is all) Hope that makes sense.

[@xerxes456]

Hello scannerdanner I also bought your great book, Ericthecarguy helped me find you and I have watching he's video same problem and he also turned the nut to bottom and now you learned me to diagnose this problem. You are the best teacher I ever seen and great personality easy to listen to. can watch your videos for hours never bored thanks man.

[@rehlek]

ScannerDanner i've had quite a few hondas with this exact same issue, and ive had great success on disassembing the valve and cleaning it out with carb cleaner or brake clean, and reinstalling. after that it worked perfectly everytime with no adjustments required. just for future reference maybe give that a shot.

[@timmyoshaunessy1518]

You are definitely the best. You not only experience but to be honest I give you a A plus for knowledge

[@ieat10milesforlunch]

dude your freaking livesaver!!!!!!!!!! i finnally found out what causes my fluctuating idle!! once again thanks a lot !!!!!!

[@ScannerDanner]

thanks so much!

[@moxie-max334]

For real right here with you man I was losing my mind lol

[@richardashcroft4596]

Thank you Professor Paul for this case study, I’m having this problem on my ‘03 Honda Odyssey w/3.5l engine. Following Mitchell1 DIY instructions I don’t get to radiator fan coming on point before my TCS light comes on the dash. Will be diving into your book.

[@42WallabyWaySydney]

Did you get it figured out?

[@omarG19100]

had rhis issue this week . i cleaned out pirts with csrb cleaner and it fixed it. but good to know the adjuster is there in case it decides to come back. good work.

[@chrishouser1213]

This video is awesome. I found this problem a long time ago but the way you explain it is great. It fills in a lot of blanks.

[@ScannerDanner]

Great to hear!

[@bossbaby5743]

This fixed an issue I’ve been having for months, tightened it down and works like new again! Thanks so much!

[@ScannerDanner]

Awesome

[@ScannerDanner]

yep, it is your main input for engine load and has the biggest effect on fuel delivery

[@jorgel.otarolam.3241]

What a master class... man. Thanks for sharing your knowledge, you help a lot of people who own a Honda. Very well explained.

[@YouTube.TOM.A]

Your work is greatly appreciated. I think that the cold idle unit fails [degrades] sometimes like a thermostat fails. It is a thermostat certainly, with wax and a plunger in a sealed chamber. after many oscillations the plunger develops small leak against the cylinder walls,so the wax pressure may not be as forceful. I am guessing that is why when you close-in the passage you still have some plunger movement but not the ideal stroke distance. the internal spring forces the piston back on cooling

[@ScannerDanner]

agree, especially because you have an electronic IAC on the same system

[@MrRyanthegreat1]

Great videos! Makes me want to run out and buy a digital scope for troubleshooting. I believe the fuel injector shut down you are seeing is not to control idle speed but rather a function of deceleration fuel cut off (DFCO). On a B18B1 as you have in the video the DFCO is active anytime engine speeds are over 910rpm and throttle position is closed. The only other fuel cut mentioned in the factory service manual is the rev limit fuel cut.

[@1DirtbikeBoy]

just got my first honda and it does the loopy idle thing. im gonna give this a shot, thanks man you've earned a new subscriber !!!!!!

[@holton345]

This is my specific issue, on a 2001 Accord Value Package (like a pimped out DX - not exciting, but hey, almost nothing fancy to break over time). It has the F23A5 non-VTEC engine and the surge is *identical* to this. I was about to swap out the electronic IAC but will look at the Cold Fast Idle Valve tomorrow. I will also look for any obvious vacuum leaks. Not ruling anything out at this point, but am glad you gave me several things to put at the top of my list. Thanks!

[@jayrist7040]

loving the video, my integra has a surging idle and i think this might be my problem, i had cleaned my idle air control valve and the problem never left so hopefully this can help me tomorrow

[@MichaelMantion]

This is by far the most useful video on the subject. Perhaps one of the most useful videos on you tube. TY.

[@ScannerDanner]

wow! Thanks so much!

[@puppetmasterblaster]

I found it pretty worthless to be quite honest with you. A lot of extremely technical garbage that in real life had no value at all to me. In my case It was a matter of playing with Hondas ridiculously stupid throttle cables, and some bad injectors that finally solved my issues. And still have a surge only in Park. So on with my search for some actual helpful info I guess.

[@alfonsohernandez5907]

Puppet master I’m having same issue This video was informative but my integra still surging while idling when engine is hot. We’re u bale to fix the issue. Thanks

[@brads1234]

I usually never do this but thank you scannerdanner, after watching this video and having it all explained out, you helped correct my idle issue on my integra. Thank you!!!

[@ScannerDanner]

Thanks so much! If you need help in the future. Post here: It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there. Paul Danner (ScannerDanner) www.scannerdanner.com/forum/post-your-repair-questions-here.html

[@ScannerDanner]

good question, I am not 100% sure on all of the inputs that are being "watched" before the ECU decides it doesn't like the idle speed anymore. I know ECT and TPS are involved and also a run timer.

[@shameelali2549]

Great detail with the trouble shooting also good to see exactly why the injectors we're shutting off :)

[@thromboid]

I believe the injector cut is actually just the DFCO logic - if the throttle is closed and the engine speed is above some threshold RPM, it'll stop injecting fuel. It just happens that when the idle is fast enough (say due to a vacuum leak), it'll hit that threshold and start oscillating,

[@ScannerDanner]

close, i didn't say it would be rich. i just said the PCM will add fuel in reaction to MAP voltage increase. If you think about it you have extra air (vacuum leak) and the fuel to go with it. so it balances out in a sense. this is why map engines idle high with vacuum leaks. Section 1 in my eBook under vacuum leak testing I have a good case study on this.

[@mctobbsi]

Thank you! Ofcourse the main point is the injectors shuting down and I'm sure you are right! Probably the pcm also wants to see a vehicle speed signal for it to go in coasting fuel cut off and I didn't think of that before so my bad on this one! Thanks again for all you effort in making this videos!

[@micbanand]

Just wonna thank you! I'm a multiman. know alot of everything. why because I just love to do things myself. Why is it so easy. to be very good at stof. Because of People like YOU. Thanks

[@Writz1995]

Adjusting the TPS until idling smootly solved the same problem. Maybe the surface of the TPS's resistor is worn, and needed to be adjusted slightly. It's running for a few days now like a dream. Hope it helps.

[@JasonTylerRicci]

So glad I found your video! This video is phenomenal. My SOHC has exact same idle surge. Now I know where to start. Thank you!

[@jeffreygomez7360]

Seriously I had the same issue about a year ago, it was the iacv. I’m having the same problem again n I want to blame the iacv, but it’s still kind of new. So I’m gonna check the fitv tomorrow. Thanks for the video.

[@kristopherbell9885]

Excellent! learned so much here! Thanks Paul! Great explaination and investigation! Its not just hondas, this happened to my suzuki g16b motor from a baleno

[@A1Diag]

I think the threaded part is how the valve is installed and held into place in the housing. I would tighten it down to keep it from backing out again.

[@sonsabbaththarebel1443]

Dude so far you have been a great help to me can't thank you enough.

[@Pdubforever1]

awesome video. Im actually in the process with the same issue on a Honda Pilot with the exact same surging issue. I also performed the same test covering the hole to the iac valve. and made a world of a difference. So Im going in confident with replacing the iac valve. BTW, Eric the Car Guy actually has a video explaining how to turn down that adjustment It touches on the exact component you showed in the video.

[@brett6754]

ScannerDanner you are of the few analytical thinkers out there. Thank you I have a better understanding now.. Even more than my local mechanic (^^,)

[@jacoblahr]

I drive a 95 honda accord and it just started doing this bullshit. Thanks for the info i just went and checked under my hood for that cold fast idle valve and its there. I know what i gotta do now👍

[@ScannerDanner]

makes sense for sure, so if this is the case with this one, all I did was put a band-aid on it. Do you think the seat could have moved? It turned pretty easy on this one.

[@ScannerDanner]

thank you so much for the comment and for your support!

[@bentan4334]

I should have seen this video before I decided to do overhaul on my engine Acura Integra damn.. you rock buddy!!! very helpful video ever...

[@XxiBeastBoyixX]

i love full diagnostic videos! every second was filled with knowledge. keep up the good work! new subscriber!

[@ScannerDanner]

Awesome, thank you!

[@jHuff-dm7lz]

For any individual video section, 45 days is good. I think one has to just plan on how much they want to bite off in a particular 45 day period. I mean, if you are going to be busy, just get 3 or 4 section for 45 days. If you are a little crazy about what you do with engine then get them activated all at once. But 45 days is a good starting point for getting to know where you want to be. i.e. how many section you want activated at one time.

[@rinamcgrath7556]

2000 crv surging idle. Don't buy any parts. I know what it is. Take off the big air hose, now see a small water hose going from near the upper rad hose where it connects to the engine. Follow that hose up and around to a connection on the throttle body. From there the water is supposed run through the fast idle thermal solenoid (that first cap, then through another hose to the IAC motor, then return to the cooling system. Short explanation, that water system is plugged up, which never allows the fast idle thermal solenoid to close and the computer tries to compensate with the IAC. Can't do it, so it goes into an oscillation. OK, so now you kinda know how it works. Take the whole throttle body off; it's easy, two bolts, two nuts, two little hoses, two electrical connections. Take off the parts that the water runs through and clear each part with drill bits, scrapers, or whatever you have. Clean everything up so you can blow air through it. Cap, fast air solenoid, must be removed and cleaned out including the water passage in the throttle body. Put it all back together and enjoy the car running like new.

[@ScannerDanner]

that is because most "professional mechanics" don't know with 100% certainty what the problem is. Truthfully there are times when I make a call, that I am not 100% either. I strive to be, I show methods on how to be but we are still human. Think about a doctor and how many times they get it wrong. Why don't we hear the same thing? I'll tell you why, because insurance companies foot the bill. When a doctor makes a bad call how many of us tell the doctor we want our money back?

[@ScannerDanner]

:-) After I shot this video, I did watch one where Eric was adjusting one of these. I don't remember what he said about it or what his setting was. I'll have to watch it again.

[@piano4785]

Eric said to run them all the way in....

[@paulremmey8268]

@@piano4785 so that just eliminates the operation of the valve ? I was wondering about how many people just take this valve off

[@ScannerDanner]

i understand it is frustrating. i don't think it was intentional and you should give that garage another chance to make it right.

[@xtrongarage9666]

Very educational video I learnt a lot from it and me being a Honda enthusiast. Just having a low idle issue on a H series engine that I need to fix. Pretty sure it's the Idle air control valve on the front intake that should be my issue.

[@xtrongarage9666]

IACV. Which dance for idle air control valve. That wasn't the cause of my problem it was just a dirty throttle body. Needed extremely good clean She runs like a dream now. I even made my own video on my own personal experience with this problem. If anyone's interested.😉

[@hondothehonda4759]

@ScannerDanner great video you’re very educated I love your video, first one I’ve seen but am impressed with the amount of knowledge you give people instead of just summarizing the problem🙏🏼🙌🏻👊🏻

[@pob_car]

I’m thinking of just deleting the fast idle valve on my Acura cl. I always warm my engine a bit before I drive it and I feel like it would be better to not have 2k rpm on a cold engine and I just want it to idle low weather it’s hot or cold. Does that sound like a good/bad idea?

[@ScannerDanner]

thanks jerry! i really appreciate the comment. let me know if there is any other lecture video you would like to view again. I'll open it up for you at no cost. BTW as a loyal customer, do you think 45 days is long enough for the streaming videos? i was thinking of increasing it

[@ScannerDanner]

on a MAP engine there really isn't un-metered air like you would have on a MAF engine. This IAC leak is exactly what a vacuum leak would be on this design. so, yes, in a sense, it is a vacuum leak

[@jackjonson2696]

ScannerDanner hi i have this same problem with my honda civic 2001. I dont have the part that u tightend with the screw, i took out the tb but dont have that ??? Thanks

[@nottyvondutchmusic2354]

I've had those valves back out on me quite a few times. Snug em up, and it usually solves the issue.

[@gt35rv12]

The screw becomes loose inside the valve and needs to be tighten

[@KaldekBoch]

Actually I should add that the motorbikes do not have a secondary IAC so the idle speed is manually controlled by an idle screw for when hot, and mechanically controlled by the fast idle wax unit when cold. The adjustment is much harder on the bikes because if you stuff it up, then the bike can have terrible until until it is *fully* warmed up. I've since replaced my Honda with a BMW motorbike which has a much more intelligent digitally controlled idle air speed via an IAC stepper motor.

[@ScannerDanner]

sweet man, thanks for the tip. makes me feel better about what I did in the video.

[@anthonyjarosz3444]

Best vid out there had this problem forwver thought i would never fix it thank you so much props to u best vid ever

[@ScannerDanner]

okay thanks for the feedback. let me know if there is any that you want to watch again.

[@angeltrieber]

my husband bought a 97 dodge neon with the same thing it surged he sent it to a garage and they wanted to charge $2000.00 to rebuild the motor we took the car back he went to check the air filter and found the massive air flow boot was split on the underside he changed it the car ran perfect so that shows how much garages try to scew ppl

[@rsanch8695]

Mr Scanner That was a life saver so far. I have a 92 honda accord. And I have a blown head gasket which obviously leads to alot of over heating and coolant leaks. I'm in the process of getting it fixed but recently this idle surge just started happening. I'm wondering if its due to the head gasket and coolant issues? I'm definetely going to do the air test Saturday

[@PupDume]

having the same problem on an EK i just bought doing this exact same thing so tomorrow going to try this out and see what happens. Thank you

[@mingemango]

Thanks mate, I did this today and it now idles properly. Keep up the great work..!!

[@KaldekBoch]

Hi Dan. Honda fast idle wax units are indeed commonly adjustable - they have been used for years on Honda motorcycles. They generally are glued on the threads at factory so the thread doesn't adjust by itself. Often between model years the adjustment on the same part is tweaked a little, when other things change such as injector models or fuel maps. In brief though they are a stupid device. Why on earth Honda put something in which the ECU has *zero* control over is just idiotic.

[@shortyboy1986]

Ya my friend had the same problem on his 93 integra and I adjusted it n BAM ran fine I think that's crazy. I'm guessing over the years it gradually loosens up then it starts rev high

[@GRowe1978]

I've had a couple of Volkswagens do the same thing. In both cases, it was the coolant temp sensor.

[@ribak1983]

thanks! fixed 95 civic ex,now it runs like it should

[@happy543210]

That wax pellet technology has been on Hondas since the 80's. I had an 86 Accord with the same device and it was a carburated engine.

[@mischief.ej1]

THANK YOU , FIXED THE ISSUE ON MY 94 CIVIC

[@davidtruckcoe7064]

good show thanks my 1995 idle high but smooth takes over 10 minutes to lower to 725 rpm .i live in a cold rainy place 27 days rain in march

[@josephcole1416]

this has helped me a lot I have been trying to figure out this problem for a while now. I have a 95 civic vx 1.5 d15z I have a good cold fast idle but when the car is warmed up it surges and I have already replaced the air idle control valve and still did it so I'm gonna try this one thank you

[@wassername888]

My 99 crv does the same thing but only on cold days.

[@fitafterfitness9966]

Its January 2023 and this video solved my issues!

[@ScannerDanner]

Awesome!

[@bushmaster2936]

Very well done : ) Thanks for backing up ETCG's results. I now subscribe to both of you : )

[@cbobcbob100]

Dan....another great video......About a year or two ago I believe that ERIC THE CAR GUY did a video on this valve,.....might be worth a look....thanks again.....bob

[@carlosmartinez-ij7vf]

I've had this problem for the past week and I hope this will fix my car or if it's the throttle body gasket

[@billharding9941]

Thanks for your study. Just fixed a 1997 Honda Accord EX VTEC thanks I your instructions.

[@headsup5819]

Simple videos are always the best.

[@joshaden6533]

This video is incredibly well done and full of great info. Thanks!

[@HighestRank]

Could have been better in focus on the scope screen but at least it wasn't fighting for autofocus.

[@rogueforce50]

Have a 2005 honda civic which started this idle issue day before. When i block the hole in the throttle body, the idle returns to normal. So I figured it’s a bad idle valve stuck open. Waiting for replacement part