Wierd idle problem

[trueblue01]

I have a 91 coupe, stock bottom end, h/c/i. Never had a problem untill now. I put tailpipes on and now my idle fluctuates between 700 and 800 rpm. Any idea what would cause this?

 

[BatFink]

MAF or IACV?

 

[WhiteFizzo]

+1 for IAC valve.
Clean it out or get a new one.

 

[trueblue01]

Ok i pulled codes and got a code 11. Then i disconected the battery and cleaned the mass air and iac. I will see what happens now.

 

[poneypower89]

If all you got was an 11... then your car isnt throwing codes. 11 means system checks out ok (on the engine off pre-code). Any codes you get AFTER the car throws 11 are the codes to look for. If you aren't getting any then you have no problematic codes in ur puter.