Hi,

My 03 has been supercharged for three years and a few weeks ago the idle started surging when it used to be stable at 900ish rpms. The AFR would go rich then lean and then rich again, over and over. The car is running on E85 and was tuned by Jeff Evan’s 3 years ago. The car has been great, but recently I’ve been fighting this idle issue and long starts(cold or hot).

• I checked for vacuum leaks and so far no haven’t found any.
• I cleaned my iacv
• I completed a valve adjustment
• I changed out all four spark plugs (#8 NGK)
• I replaced and relocated my battery to Optima red top 800 CCA. (Try to help with long starts)
• I replace my AEM fuel pump (old one is now spare)

I replaced my wideband O2 sensor (old one is now spare)

I can upload a cold start log and idle log from my AEMTuner if someone can help me troubleshoot.

Thanks in advance.

 

Try a Map wack,ie tap your Map sensor with something while reving engine

 

Okay I’ll try that when I get home. I have the Skunk2 4-bar MAP sensor btw. Got that new about 3 years ago.

 

You cannot clean the IAC. It needs to be disassembled, and the shaft freed up.

 

Thanks everyone for the help. I tried replacing the MAP sensor and issue is still there. I’m on a flex fuel tune and the idle was great after filling up with 93. Idle fluctuated a bit with E85. I reached out to my tuner, got a retune and idle is better.

 

Thanks Billman.

BTW - It’s time for me to get my TCT replaced and I’d like to get one from you. Can I get details please? I’m located in Georgia and I do have PayPal.

 

PM sent ^