Hey guys i recently been experiemcing this problem with my 03 evo 8.

Now my afr reads rich at idle. It stays at 11.2 - 11.4. I also have this wierd idle problem. Before my car would idle at 1000 now recently i noticed it sitting at 1200 and then dip down to 1000. Another thing i noticed is that out of randomly my rpms would shot up to 1500 then back down to 1000, then there would be times when my rpms would dip down to 400 and almost stall out. Car is tuned. Does anyone know what this can be? Thanks guys

 

Have you tried doing a boost leak test, cleaning of the MAF and checking the IAC motor?

 

Boost leak ? Do you idle in open or closed loop? Check the o2 sensor if it's closed loop

 

Thank for the reply but if its a boost leak wouldnt i run lean at idle, and rich at wot? And yes i cleaned the maf but no bueno. And how do i check the iac motor

 

How do i know if its open or closed? Thanks!

 

I would pull the negative terminal off the battery then pull off the iac and clean the area and clean around the IAC itself.

if i remember correctly a leak could run richer at idle

 

any codes I would Tbolt clamp and zip tie down all the vacuum lines. then boostleak test it. when my mad was bad it would cut me out of boost real quick and shut me down as soon as I hit 6psi it felt like I hit a brick wall. What made it ironic is the fact that the mad didn't even shoot a code,

 

Ok is the iac the same thing as the isc? Or diffrent things.

 

ISC? The IAC is located in the TB, just under the opening where the UICP goes. It's a black piece that has 3 small screws holding it on