For months, I'd been fighting a very hard-to-find problem on my 1994 Gen 1. Symptoms were erratic idle, very high idle, check engine light immediately after startup, and generally running like crapola. The only OBD code was 25, short/open in AIS circuit. After replacing the idle solenoid a couple of times (and every other engine sensor as well), I finally took off the upper wiring harness and tested for open/shorts/intermittents. This led me to find that the harness connector to the Camshaft sensor had pins that had pushed back into the actual connector, thus not making a reliable electrical connection. (The faulty pin WAS the Camshaft signal line to the PCM.)
The harness and connectors, now over 30 years old, had become brittle (fragile, actually) with heat and time, and the pins were not secure anymore. The Camshaft Sensor Connector, as well as a couple of sketchy others (TPS and temp), also received new connectors. Connectors closer to heat sources were more suspect than the cooler ones.
Just a heads up for us older car owners... it might be your wiring harness!
The harness and connectors, now over 30 years old, had become brittle (fragile, actually) with heat and time, and the pins were not secure anymore. The Camshaft Sensor Connector, as well as a couple of sketchy others (TPS and temp), also received new connectors. Connectors closer to heat sources were more suspect than the cooler ones.
Just a heads up for us older car owners... it might be your wiring harness!
