MX-3.com

my quest for smooth idle is documented on this site, and i can say finally AFTER ALMOST TWO YEARS... PROBLEM SOLVED!!! i went to get my injectors cleaned as i was leaning towards a problem with them... recap: bad fuel economy, acceleration problems, erratic rough idle. he basically made a good argument for my cat being the culprit so i gave him the green light on a high-flow cat. ive only driven it back from the shop, but ALL DRIVABILITY issues are GONE. not sure about the gas mileage, but im anticipating it will be better.

is this on a K8?

where did you get your high flow cat?

its on a b6. i got it at meinekie. i probably would have saved some $ if i would have got it on ebay, but this one came with a warranty. i ran it on the highway today. pickup is a lot steadier & stronger (used to feel like i was towing an anchor sometimes). i was getting 16-17 mpg; i just filled up so ill let you know if i see an improvement. idles really quiet now too. other things ive tried: motor mounts, full tune-up, seafoam, breather vent tube replacement, iac replacement (which was bad but didnt fix all idle issues). quick iac test: if your car bogs down instead of idling up as soon as you hit th ac, your iac isnt working.

did you start getting any engine codes after you seafoamed? for some reason mine turns on after i did it, not all the time but probably like everyother day. It clears it whenever i turn the car off and back on, do you think its an o2 sensor?

i was getting an engine light every couple days that went off when i turned off the engine. i pulled the code and it was an o2 sensor code. i swapped in a new one and havent thrown a code since. try rockauto.com they had closeouts on our sensors for $35

ive tried looking on ebay but didn't see any high flow cats. Only saw cheapie test pipes.

eyezpinned, any word on the gas mileage?

I would suggest getting a magnaflow hi flow cat. it's about 60 bucks, and they're emissions compliant.

eyez? ... Did it feel like you'd be going down the road accelerating and it would go good then feel like you kind let off the gas, then again and again? and slow accelerating?
let me know cuz thats the problem im having.

i've got a problem with mine...its an old engine.
When i accelerate a little too fast it will sputter and die (sometimes even backfires). If i accelerate slowly (really slowly!) it will gradually build up to speed and runs fine (happens in every gear).

Smooth - do you have v6 or the 4 banger?

in the v6, I find the injectors can be a leading cause of the whole, "oops, I let off the gas even though I didn't let off the gas" issue, kinda annoying, just jerks back, then jerks forward while going down the highway.

I pinned the problem to two issues: Fuel Injectors and spark.


This might be your issue as well drumx3.

Always, always, before asking for help, let us know if you've done your tuneup. Oil, spark plugs, wires if you've not ever done that, disty cap, rotor.

If you plan on keeping your current setup and have not done so, have your injectors professionally cleaned and rebuilt. Witchhunterperformance.com (I think?) does both side-feed and top feed, and both are easily cleaned. They also replace all the o-rings and I think the pintle caps? not sure on that one.

I had my ZE's injectors cleaned and it did WONDERS and fixed most my problems.
Didn't solve my running-into-sidewalk problems, though.
And it didn't repair my cracked disty cap.
And it didn't order me fries, even though I was really hungry.

for both you guys w/ acceleration issues i suggest replacing fuel filters and having timing checked/ reset. sorry for not replying sooner... since my last post i've done both and the affect on acceleration was far more noticeable than after just replacing the cat

Since i first got my car it's felt like this. Sometime when im on the gas i feel like the car get a boost of power, like i just spray'd it or something. So that lets me know that K8 isnt as slow as what i think and all my friends think. Its just been slow as hell since i got it and i knew there was something holding it back. Probally in about 2 weeks im gonna replace alot of things. I'll probally start with the fuel filter, then plugs and wires. I'll probally change the cat next, and if all that doesnt do anything, ill throw some new injectors in. Doesnt injectors cost alot for this motor? I know they were really cheap on my last car. I bet it would feel so much better if i could get this problem fixed. right now, to me it feels almost like the sohc in a mx3.

Oh yeah, my intake manifold has a loud airy sound to it. is it suppose to sound like that?
I think it's coming from the manifold. kinda like.. i can hear it suckin air or something. even with the hood down, and with me going down the road, ill go past another car and the sound kind echo's off that car and i can hear it. thats how loud it is.

don't.ever.say.it's.as.slow.as.a.sohc.

Can you go over 40mph? OK, it's not as slow. Ever.


The "windy" sound you're hearing is (at least what I've been told, I've only driven in one K series car, my own) is long intake runners. Supposed to sound like that.
At least, it better, mine does the same thing. I kinda like it

purchasing new injectors will be expensive, especially since you have to buy a set of 6.

The cheapest option is to have yours professionally serviced by someone who can clean them OFF the car. They will flow just as good as brand new injectors. $17/injector.

get some cheap NGK G-power copper plugs, like, now. If you haven't changed them since you got the car, just for peace of mind, please do so. O2's would be my next step, another cheap and important maintenance.