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1999 GMC Sierra 1500 - Starts but dies

350 cu. in. V8. My truck starts and dies. I try immediately after and it will crank, but not start. It seems to start fine in warmer weather like summer. I tried adding a can of Heat, thinking condensation was in the gas tank. No help there. There are many forums suggesting a variety of things but no one sure answer. Fuses look ok. I disconnected the battery and cleaned the terminals of some corrosion. Same result. My key has had difficulty turning on, but if I turn the key over, it turns fine. I’ve waited until the security light goes out- @5 sec., no help there either. I can hear the fuel pump run when key is turned on. It seems there is a little better result if I hold the throttle down a little when starting the second time. In very cold weather, the engine sputters somewhat while starting. After it’s finally started it runs great. Idles fine. Appreciate any help given. Thanks!

The problem might be a bad Ignition Control Module.

image

ICM’s function in two modes.

These are the start and run modes.

When starting the engine, the ICM is in the start mode.

The ICM allows full battery voltage to the coil to make sure the spark is hot enough to start the cold engine.

Once the engine starts, and the ignition switch goes into the run position, the ICM goes into the run mode.

The ICM then drops the voltage to the coil so that when the charging system comes on line, the higher voltage doesn’t burn up the secondary ignition components.

So the problem may be that the ICM works sometimes in the start mode, but never in the run mode.

Tester

Can the ICM be tested and where is it located? Thank you for your quick response!

Check for spark.

Tester