Weird idle problem

[Kyle97-clipse]

Ok so here is whats happening, sorry that its going to be so long just want to share all the information I know for better responses.
Ok so my car was idling fine when completely stopped but whenever the car was coasting and you pushed the clutch in, even if it was in neutral as long as the car was moving it would idle at 1500, until I stopped where it would return to about 750. Well it got worse and started idling higher even when stopped. So tested iac got 62 ohms so figured it was bad, just put a new iac in today and now it is idling fine again when stopped but still up at 1500 when the car is moving. So I started testing and playing around with all the sensors like map and tps, but didnt get anywhere there. I reset the ecu by disconnecting the battery, apparently bad idea. I was told that when you reset the ecu it has to learn fuel trims or something like that, which I hope is the case because now up in the higher rpms it backfires and the check engine light will flash during this. It has brand new spark plugs so its not that. I am so frustrated with this idle thing, I heard something like a vss problem also, I'm going to check into that, because like I said it only idles high when the car is moving if you stop it idles perfect, im so confused. Any help would be appreciated, thanks

 

[Fotowntalon]

i had this problem to, unfortunently i kept upgrading and gave myself even more problems before it got fixed so not 100% sure what fixes it....

Anyways yes the ecu does have to relearn things, but it shouldnt take that long depending on how many upgrades you have. Your backfire could be another new problem entirely so keep that in mind.

Your idle problem could be due to something as simple as your TB sticking, so make sure its clean, and replace the gasket while you have it off, that could also eliminate a vacuum problem at that location.

All in all just try to keep a cool head, I know i can be a pain to keep from beeing frusterated, but its uneeded stress.

 

[flying_eagle]

Mine is doing the same thing but it stops when that car warms up i dont know if there is a connecting but it started when i installed the maft, i re adjusted the maft for the fuel trim and it fixed it but i got the trims wrong so i adjusted it again and it started again so it might be the maft or something to do with the fuel trims

 

[Kyle97-clipse]

Your idle problem could be due to something as simple as your TB sticking, so make sure its clean,

This I did do today while it was off, there was actually quite a buildup in there, but all clean now

 

[420a_turbo]

I had idle issues until I did the EGR block mod. I could've been the TB getting stuck too, I cleaned that at the same time.


Have you tried reading the CEL? Checked the idle speed sensor/TPS?

 

[Kyle97-clipse]

I dont really want to waste money on things I dont need but, first I'm going to check the vss. If that looks good I may buy a new tps and see what that does.

 

[Locke]

Most sensors and systems can be tested with a multimeter; proper diagnosis can save money, since you won't be replacing random parts.

 

[Kyle97-clipse]

So decided to see if it would misfire or not today, and it did, its still doing the same thing. Right at about 6k it will spit and misfire and the check engine light will flash. I'm going to change the plugs tommorrow and check the coilpack even though its an msd.

 

[Fotowntalon]

I had a msd coilpack, worked PERFECTLY for up to around 8 months.... very dissapointed with its quality...