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?
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.