I've replaced the IAC recently. In fact, prior to replacing it, the car would not maintain a consistent idle. After replacing it, it would like around 700rpm, where it used to - but was rough and obviously had a miss. However, the computer would not enter diagnostic mode. I changed the MAF as part of the troubleshooting for the rough idle, as I had not identified the reason it would not go into diagnostics. Troubleshooting resulted in identification of an internal ground failure on the ECU. After replacing the ECU, I got the high idle. That allowed me to pull codes that indicated EGR issues and inability to adjust idle. I thought they may be related, so i replaced the EGR solenoid motor and all the related vacuum lines. No change to behavior. Sprayed some brake cleaner around to confirm no vacuum leaks. Install of old MAF reduced idle, but was inconsistent...
I have a mechanic friend who says he can connect his reader to my obd 1 and see what the sensors are sending, in order to determine what may be out of spec. My hopes are to see him Sunday of this week... I may still replace the EGR Valve, EGR Sending unit and TPS, as they are all nearly 30 years old... we will see.
I have a mechanic friend who says he can connect his reader to my obd 1 and see what the sensors are sending, in order to determine what may be out of spec. My hopes are to see him Sunday of this week... I may still replace the EGR Valve, EGR Sending unit and TPS, as they are all nearly 30 years old... we will see.