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rickwilcox · Jan 7, 2012, 08:58 AM

I changes the icm and cleaned the carb out too. It ran great for about 1/2 hour. I shut it off and then 3 hours later I went out and started it again and I had the same problem as before. Rough idle and quit, then starts right back up again and runs fine, then it starts to do it again. Any idea what it could be now?

TxGreaseMonkey · Jan 7, 2012, 10:07 AM

Thoughts:

. Coil may be breaking down.

. Some other problem with the distributor.

. Check for codes.

. Are you using ACDelco spark plugs?

. Check the Engine Coolant Temperature (ECT) Sensor.

rickwilcox · Jan 7, 2012, 10:19 AM

Yeah they are ac delco's. How do you re set the computer and clear all the old codes... could that be the problem? The distributor looked fine inside, could it be the 02 sensor? Would a coil break down like that because it runs fine for 20 min to 1/2 hour and then start it back up again after a while, and it does the same stalling/hesitation.

TxGreaseMonkey · Jan 7, 2012, 10:29 AM

Good idea about clearing codes. Try disconnecting the negative battery cable for 15 seconds. Coils break down under load (heat)--20 to 30 minutes would be ample time for the coil to overheat and fail. I almost always recommend replacing ICMs and coils together. Many people, however, want to save the money and don't do it.