This just started happening to me yesterday. Basically the car when in neutral idles very low and lumpy and stalls also on when it's idling my aem wideband shows my afr to be in the 10s...Anyone have any ideas to what it could be. It's has similar symptoms to when you have a VTA bov setup, the only problem is I do not, I recirculate. I checked my forge bov and even swapped bovs to my friend's evo x stock bov but the car still has the same issues. All my hoses seem to be on, no boost leak. I'm thinking maybe it's my ISC or MAF sensor? Anyways, any info would be appreciated. Thanks in advance.

FIX: For me the problem was my Idle Speed Control Valve that died on me. Replace that to fix the issue.

 

Bump

 

have u checked ur front o2 senso to see if its working fine ???

 

The one on the exhaust manifold??

 

if you have done a proper boost leak test, check the maf and make sure its plugged in...any other mods you have so we can help you out

 

maf tested, how would a boost leak effect the idle/stalling??

 

lets go 1 step at a time

1. first can u log the car do u have evoscan ??
if so log the car to see the voltage ang how the front o2 works , from ther we can determine if the o2 is damaged

 

how r ur afr when driving ????

 

Found the problem. It's my idle speed control valve. Once i swapped my friend's evo 9 ISCV my car ran perfectly. Thanks to everyone who tried to help :-)

 

Well, i am having problems like yours but, well not really. At idle mine is fine. It used to just happen if 5th gear going down the highway, the pedal would start to feel heavy and the a/f would go rich rich. I would have to let off the gas and then start back again slowly or downshift to get back to around 75. Now it seems it can happen in almost any gear. If i try to just cruise through the gears from a stop and not try to blow the soccer moms mini van out it will do it.

 

When it goes rich rich are u in boost

 

Sometimes yes, sometimes no. Like just now I had to go to the post office downdown and at one point there's a stop light on a pretty steep hill. Starting off it when straight to 10(its a narrowband on my TT) ans I was like ok I will shift into 2nd, it did it in second. Had to give the ol finger to a few innocent bistanders for honking and what not, ha. That one was bad though. It took about a block and a half to recover. Another thing I noticed is sometimes when at a stop light the rpms will go up to about 2k and then settle back down. With ac on or off it still does it. I know my bov is leaking which sucks because its my 3rd and its pretty new. I guess I will have to buy another and send this one back.

 

did u check ur front o2 sensor activity to see if its telling the ecu that ur lean when ur really not, this could cause going rich on idle sir

also i would recommend for anyone having issues like going to rich , because this will damage ur oil by contaminating

do u have evoscan ??

 

I dont even own a laptop atm. i have not checked my front 02 sensor. It is brand new. Right now my car is warming up even though there is no one in it but every now and then it sounds as if someone is in it and revving it up to about 2k slowly for a few seconds then letting it off.