I have a new to me 1989 Iroc Convertible 305 auto. When this car is cold it starts and runs great. I can run it for hours stopping, shutting it off, restarting and running some more. Then I let it sit for an hour or two and the darn thing spits and sputters and then dies, sometimes it won't start, sometimes it will and I can baby the throttle, limp it along and it seems to clear out after 10 minutes. Sometimes I leave it till the next day and when it's cold starts right up and runs like a champ then it starts the whole process all over again. It has thrown codes #23 Intake Air Temp, #42 Ign Bypass, and #43 Knock sensor.

First thing I do is find the Intake Air Sensor and whalla! No wire attached, simple fix I think but I cannot find the wire for the life of me, should be tan/black. Somewhere I thought I read 89's don't have this Intake Air Temp sensor. Is this true?, is this why I have no wire?, the sensor is there, right by the coolant temp sensor. Something is heating up when the car is turned off creating this poor running issue. Does anyone have any suggestions.....Anyone....frustrated

Recently replaced plugs, fuel filter, coolant temperature sensor, adjusted Idle air control, TPS and cleaned the MAF. This issue was present before these items. I have read high and low on this site, now its time to ask. Sorry for such a long post.

 

the coolant temp sensor wires should be in the same section of the wiring harness as the iat sensor, I'd start tracing down from that sensor and see if you can find any loose wires

 

Yeah i've opened up the loom where the coolant temp sensor wire goes into but am unable to find any unaccounted for wires, Ive followed it back to the firewall and have searched all over the engine compartment. Nothing.