My 1991 Pontiac firebird is due for an emissins test. It has been hesitating on acceleration at low speed only when cold.
A mechanic friend connected a special monitor to the car and read a code 35(IAC problem). One sevice manual I have states to replace the IAC valve. Another says it could be either the IAC valve or TPS sensor. Upon checking the TPS visually ther is a wear patern where the shaft is inserted. Do you feel I really
have to replace both,or is it the IAC valve,which was replaced
2 years ago and allways worked well previously?
Before rpalcing the IAC try taking it out and cleaning the pintle on it and housing it came out of with a good carb cleaner ....
when you pull the iac out look at the pintle and see if its been seating right ....there should be a sign of wher its seatiing on the pintle seat ....
tps needs to be looked at with a scanner ...to see volt movement when you press on acelerator...
most likely hav a carbon build up
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