I have a random miss fire at the speed 50-60 mph it comes and goeS not constant pick and chooses needing a wiring schematic to trace wire's from the injectors to the ICM to the Crank and Cam sensors?

SOURCE: miss fire #3 cyld. compression 125psi idle speed 2500 rpm

Hi

A faulty IAC would cause a random misfire rather than a misfire in a specific cylinder, as would an intake air leak, both of which would cause a high idle amongst other things.

Run the engine until its good and hot, disconnect the injector harness plug so the injectors are disabled, remove all the spark plugs, disable the ignition by unplugging the wiring connector(s) from the coil pack(s), and then carry out another compression test on al the cylinders.

If the compressions are now all relatively the same then you very highly likely have a faulty injector in cylinder 3.

Very best regards

Geordie

SOURCE: multiple random miss fire

Now change the distributor. Get one from salvage or e-bay. Did the timing belt jumped a tooth or is it new. Vitally

SOURCE: 02 cavalier with no spark on cyl 2 and 3

did u replace the wires? You might have power but a bad connection to the spark plugs or just bad spark plugs. just a thought

Mike LaPres

• 757 Answers
• Posted on Dec 31, 2009

SOURCE: 03 grand prix mis fire codes

It may need a "CASE learn."

SOURCE: my wife caravan grand 3.8 has a bad idle ,one day

CHECK THE , PCM AND IT CONNECTIONS . IT COULD BE A SHORT ON THE WIRE HARNESS THAT,S CONNECTED TO THE TCM. HAD THE SAME TROUBLE .