I have an 04 Monte with a 3800, over the last 3 or 4 years we have had to change the Ignition control module 3 times. Every time we changed it the old one always tested good, but changing seemed to fix the problem until now. it will start up and run for 3 to 4 min and then just shuts down. I have changed everything i could think of except the ECM & BCM. any suggestions

 

Could be:

Crank sensor
Cam sensor
Wiring short
PCM
Ignition switch

 

Since manipulation of the control module (and the wiring connector) seems to "fix" the problem I would suspect a dirty/bad connection in the connector or possibly a broken wire in the harness.

 

Years ago I was chasing an intermittent problem down where my Grand Am would go from running fine to mis-firing and the computer just dumped more fuel to compensate. By RANDOM chance, found the problem to be a bad coil (I was inspecting, wiggling wires and such while the car idled, found placing my hand on one coil, I could make the problem come and go). Replaced it with a known good spare, never looked back.

If testing the ICM comes back good, odds are it's coincidence as to why the problem "goes away". Could be as simple as a bad wire.