my 89 with 302 and 5spd 4x4 has been in and out of shop every time I get it back from them my Check engine light comes on after driving it about 10-15 minutes. They have replaced the MAP sensor, ECG, and another sensor. They say it works fine. if you shut if off and restart it the light goes off til running for 10-15 minutes. They only check the codes from and off position so the light is never active when they check it. Any Ideas? The truck runs great but the state will not pass a vehicle if a light is on.



Tom

 

You can tell what the light is indicating on older(pre 96) cars by using the "paperclip" method. Google "obdI paperclip" and you'll find info about it. You baisically just short two terminals of the test plug with a paperclip, then count flashes of the check engine light.

Though I believe you will need a scan tool with an OBDI adapter to clear the code. Sometimes when you fix the problem it clears on its own, but for whatever reason it often doesn't. You can try disconnecting the battery for several minutes to reset the computer.