Gutting The Pre Cats In My Pre-Facelift MR2 Spyder | Miller's MR2

The pre cats inside of the mk3 Toyota MR2 (specifically earlier models: 2000-2002) are known to cause major issues. Long story short, they disintegrate, clog the main cat and eventually blow up the motor. To fix this, one can either gut the pre cats or buy aftermarket headers that do not feature them.
I chose the cheaper route and gutted the pre cats. I'm not nearly as experienced as some auto enthusiasts and even I was able to pound this project out! If I can do it, you surely can too. This video is an informative How-To sharing my experience overall.
This is the tutorial I followed: www.spyderchat.com/threads/ho...
If you have any questions about my experience, drop them in the comments! If you liked this video, I'd appreciate a thumbs up. Otherwise, subscribe to the channel for more and we'll see you in the next one!

[@JesseGram-nr1xz]

Hey Miller, yours is by far the best how-to video on this operation that I've seen, and I've watched a lot of them. Bravo and thanks for doing it. I don't yet own one of these cars, but I'm suffering a serious passion to get one. Now I know I can deal with their one big drawback (if it hasn't been taken care of already) when I give in and start looking seriously for one. Thanks again for your clear and thorough instruction!

[@geoffburrill9850]

Nicely done sir, have the same to do on mine.

[@peyiots]

Well done!

[@johnvirgin405]

Great video. Many thanks.

[@millersmr294]

Thank you!!

[@KollynJ]

I have the same manifold cat on my vibe so I hope it’s the same and doesn’t cause and gets ride of my codes! And my mpg and idle gets smoother

[@markbellingham4536]

Think 🤔 I’ll do after market one thanks nice vidio

[@millersmr294]

Definitely easier to do it that way!

[@shanebeaudrot777]

Good video 👍

[@millersmr294]

Hey thanks Shane!

[@LA6UOA]

Thanks for the video! I'm having angst because I have to do the PreCat removal on my 2000 mod MR2Mk3 in the summer.

[@millersmr294]

sorry for the late reply! don't be too worried, if I can do it, anyone can.

[@LA6UOA]

@@millersmr294 Thanks for the reply! What I'm most concerned about is the bolts and nuts and not getting them turned. Thanks to you, I now have the confidence to do it as soon as it gets out of winter storage! Thank you again!

[@KollynJ]

@@LA6UOAhow did it go and work?

[@nicolasdominguez6624]

Did you replace the gaskets when doing this? About to take this job on sometime soon and not sure if it should be replaced

[@millersmr294]

Yes - i recommend doing so

[@nicolasdominguez6624]

@@millersmr294 👍 thanks

[@lebluescout154]

Do you know if the 1999 Models take the same gaskets ? i would assume so since they are the same gen till 2003.

[@Oyztr]

Would you recommend gutting the 03’ or 04’? I don’t really have any knowledge on cars and was planning to get an mr2.

[@Oyztr]

@@12ealDealOfficial thank you, so anything after 02 I won’t have to gut

[@12ealDealOfficial]

@@Oyztr Sorry, I deleted my reply. I'm not 100% certain after thinking about it some more, so let's hope someone else can chime in.

[@millersmr294]

03+ surely had better cats, but if it were me I’d still do it. So sorry for the late reply!

[@sicchuckie]

Thanks nice job. I have an 03 same color. I hope the 03 doesn’t have the precats. I heard you said thru 02? Does that mean not in the 03? I hope! Lol

[@Kana0211]

No 03 still has the same issue

[@millersmr294]

Edmund is correct - the 03+ cats got better but still suggest removing!

[@imtherealnick8897]

How many miles before the engine is toast? Looking at mr2s around 30-60k miles and I don’t want the engine to be beat

[@12ealDealOfficial]

One year later, how's your MR2 on the road? My pre- face lift MR2 is beginning to bog down at higher rpm, burning a lot of oil, with dramatically reduced fuel economy. This fix is my next option before looking at a rebuild or swap.

[@millersmr294]

It’s doing better than ever! Unfortunately, gutting the pre cats isn’t going to solve your oil burning. In fact, burning oil is what leads to pre cats being broken down and destroyed. Try removing the top O2 sensors and shining a light in there. You should see a honeycomb pre cat in each hole. If you don’t see any, or the ones you see have clear damage, it may be time to begin saving for a new engine. Regarding the oil burn, these 1zzs are known to start burning eventually. The rings just wear out.

[@12ealDealOfficial]

@@millersmr294 Thanks for the heads up. Wish I knew at 50K miles instead of now at 153K. Should've jumped on the MR2 enthusiast forum sooner and saw all the posts. I'll post another comment once I'm able to get in there and do the work. Thanks again for the response.

[@KollynJ]

@@millersmr294was yours bogging down as he mentioned? Accel seems slower, My mpgs are way low and I also noticed oil drip from my tailpipe

[@martinruiz2675]

After the removal ,did the check engine light come on?

[@caddiediscgolf6872]

Nope!

[@rodneygass]

Does it have more power now, can you tell?

[@millersmr294]

sorry for the late reply! i can't tell much difference, but some have said so!

[@lassydogpie5390]

I felt my spyder lost some lower end torque after gutting the pre cats, oh well least it’ll live longer

[@millersmr294]

It’s definitely worth the longevity of its life!

[@randymaizland9662]

How did you get the nut off that stud that came out? Also, how did you get proper torque on the nuts that you had to do with a box end wrench?

[@millersmr294]

I used a Vice grip on the end of the bolt and then a socket for the nut. Before reinstalling, I soaked the whole thing in PB Blaster to make sure the nut came off okay. Regarding the nuts i tightened with the box end, I didn’t torque to spec. I got a feeler for how tight the nuts I could use a torque wrench were and just tried to match.

[@randymaizland9662]

@@millersmr294 Thank you. Great video

[@itsjuskey.__]

How often should you gut the pre cats ?

[@millersmr294]

Once they’re gutted they’re no longer there, so just one and done

[@itsjuskey.__]

@@millersmr294 Since you own an mr2 is there a way we could chat with each other via text or email ? i want to know as much as i can since ive been thinking about buying one

[@millersmr294]

@@itsjuskey.__ message me on Instagram! @millersmr2

[@arlenburgin2392]

2003s are fuct too

[@arlenburgin2392]

Any codes?

[@millersmr294]

Nope