Sonoma-Engine Stops Abruptly

I had a similar problem in an older Buick, which turned out to be transistor issues in the ECM computer. It would also restart immediately, and although the dealership (was under warranty) couldn't find the problem, there was a TSB out on this particular issue (89 Regal). In those days, Buick had zone representatives, one of whom immediately recognized the problem.

Have also heard of marginal connections in the plugs to the computer, and other places in the system. Last, in one case, I had an ignition switch that caused similar problems.

There could be several other causes as well, and they may be hard to find since this is an intermittent problem.

Thanks for your prompt response. I will check the wires to the computer and also take a look at the ignition switch. Also plan to call other GMC dealers in the area to see if they have a TSB on this problem. When/if I find out the problem I will post again. In the meantime, any other suggestions will be helpful. Thanks!

Do you have a lot of keys dangling from your ignition key? I've heard that too much weight hanging from the ignition switch can cause problems sometimes. You might try using just the ignition key by itself if you are still driving the truck and see if it helps.