Ok so I had a coupler rip, and the car had a nasty boost leak for awhile, didnt run bad other than missing a bit at idle. So I fixed that and then I put a new air filter on the car. Ever since I put the new filter on the car anytime I go to slow down say for a turn or at a stoplight the AFR's go to 10 and the car either dies or barely stays alive and stumbles at ten for about 15 or 20 seconds before spiking a real lean afr then going back to idle at 14.9ish. I have no idea what the problem is, shop is telling me the new air filter is the problem but I had put my old filter back on and it still did it. Also saying I damaged my MAF but it stayed in the intake pipe and is also less than three months old. You guys got any ideas.

 

Did you unplug your battery after fixing the boost leak?

 

yeah its been doing this for about 2 weeks now, drives great otherwise, battery has been out multiple times

 

really no one has an idea? Ive noticed its alittle rich all the time nothing too bad just weird spiking at times, and when I let off the gas it goes to 10s then does the whole lean out thing

 

Have you pulled your spark plugs? Check them out, maybe they are fouled??

 

Man ot can be so Many things. It can be your tune cause the factory ecu figured you tryed to adjust it. Or your bov or idle control valve I forgot what the word is I had changed it before also. It can be a vacuum leak.

 

What air filter did you use (wet or dry type)? If you used a wet type, get some MAF sensor cleaner, clean your maf, then disconnect your battery for 10min to reset the ecu and try again.

 

what engine management do you have?

 

spark plugs are brand new,
it was a dry filter.
No vac leaks that I can find.
Where is our IAC?
and its tuned with an F/IC

 

It's hard to describe. Try to look it up.

 

I couldnt find anything.

Is it in the evap system near that little green cap on the same wire string as the MAF?

 

We don't have an IAC valve. Just FYI. It uses the electronic throttle to idle the car.

 

It's not called a iac. It's like vss or something like rats and yea it's around that evap thing with the green cap. It's har plastic damn can someone help me name this thing. Lol

 

F/IC and idle don't always get along. If all mechanics are in order, the F/IC is likely the culprit.

 

im pretty sure this is what it is. Its never idled great, but its been fine, now is getting dangerous since the car will shut off mid turn and I have no steering all of the sudden. I just wish the shop that tuned it would listen and stop saying the tune isnt the problem since it is set in the f/ic

 

The F/IC is the culprit more than the tune but there are ways to tune it better so it won't stall. Raising your IRS usually helps but dialing in the MAF and 02 map in that area and surrounding cells is your best bet. Believe me, it sucks because my car does that more now due to the hotter weather but there are ways around it.

 

I'm having the same problem, I got a Greddy kit with a Turbosmart Evo Bov, Tuned with F/IC and since I installed the damn F/IC, it has had a rough idle, it got corrected to some level, but the only way I have my car in a smooth idle(and that's some of the time) is with the AC on :/ and I have been at high speeds and as soon as I put it Neutral(to start slowing down) it quickly shuts off on me... :/

 

i recently had the same problem on my aem ems. to correct it, my tuner just took a look at the idle compensation for when the a/c is on, and set the idle compensation for when the a/c is off to the same value (mine was 10%). dont know if the f/ic has this function though.

 

Bret you going Wednesday to test and tune?

 

Are you talking about VSV?