Erratic Idle until Car is warmed up

[Eno335]

Ok so I'm trying to pin point what my issue is. Car currently has Mission Performance stage 2 tune, downpipes, and AP Intakes. So the issue I've been having is erratic idle during warm up. Like if I let the car sit for 5-10 minutes to warm up "I live in the Midwest" the thing just idles up and down between 500 and 1000 rpm. But after I'm on the road for awhile and go to park the idle is steady. Is this a MAF issue? Would a exhaust leak also be a culprit?
Thanks!

[induc916]

I have the same issue after installing project gamma intakes.

I have activeautowerek stg 2.5 flash, dp, akro exhaust, gapped plugs, intakes,

[technician117]

Since your modded, it could be multiple things related to the mods/tune. Are you still running stock MAF's? If so, you could have a bad MAF. Do you have any codes stored? An exhaust leak at the cats could potentially cause an issue like this if the O2 sensors are getting erratic readings.

[Eno335]

Originally Posted by technician117

Since your modded, it could be multiple things related to the mods/tune. Are you still running stock MAF's? If so, you could have a bad MAF. Do you have any codes stored? An exhaust leak at the cats could potentially cause an issue like this if the O2 sensors are getting erratic readings.

I believe it has stock MAF sensors. I just got a code last night and I scanned it and it was a P12A9.. ideas?

[KSA.m6]

had a similar issue with the car a while ago, didn't get any codes.
went away after O2 sensors changed

[technician117]

Originally Posted by Eno335

I believe it has stock MAF sensors. I just got a code last night and I scanned it and it was a P12A9.. ideas?

What is the description for that code? How many miles on the car?

[Eno335]

Originally Posted by technician117

What is the description for that code? How many miles on the car?

I believe it's boost pressure too high from what I've read. Ordered two new boost pressure sensors. The car is my daily and I put a ton of miles on her. She's right at 90k miles

[Eno335]

Bump.. still having issues with the P12A9 code

[technician117]

This is the only code you get? How well does the engine run?

[Eno335]

Originally Posted by technician117

This is the only code you get? How well does the engine run?

Yup it's the only code I'm getting. Also I get the code with Drivetrain malfunction and it won't build boost occasionally. Generally it's all on start up. Sometimes boost works and sometimes it doesn't. Also note at times the boost kinda of stutters as I'm accerating.

[technician117]

Originally Posted by Eno335

Yup it's the only code I'm getting. Also I get the code with Drivetrain malfunction and it won't build boost occasionally. Generally it's all on start up. Sometimes boost works and sometimes it doesn't. Also note at times the boost kinda of stutters as I'm accerating.

Sounds like you should datalog to see whats going on. Unfortunately there aren't too many cheap ways of doing that. I know Bootmod3 has excellent datalogging capability but the platform is roughly $900 with one tune map.

It's probably not related too closely, but maybe clean/replace your MAF's. They sometimes correlate ambient pressure which I believe is used in the measurement of boost pressure in BMW systems.