I have a 98 brighton with an extremely intermittent problem - it's only happened twice in the ~20k miles I've had it.

I have no CEL codes or pending codes, car drives fine... Except these two weird times.

 

Started the car and it idled at 2000rpm and refused to idle down (this recent time the engine was warm). So I shut the car off, waited a minute, and started it back up again. When it started back up it was running on 3 cylinders. Unplugging the cylinder 1 injector makes no difference at all, thus my determination it's not running on that cylinder.

Both times I unplugged the positive terminal on the battery, hit the brakes (to bleed any residual power out of the system), and plugged the battery back in. After doing that, the car runs great again.

 

The only maintenance items I've done are oil changes, spark plugs, and PCV valve.

I tried unplugging the MAF sensor and the o2 sensor as I've had those cause weird problems in the past, but no difference.

 

Sadly this hasn't happened at home when I can plug the injector harness into an oscilloscope, maybe run a function generator to the injector to see what happens if I manually actuate it, etc... Instead I was 400 miles from home hoping I could drive home on all 4 cylinders....

Change your plug wires. If it still comes back pickup a used ignitor and coil pack.

 

GD

Sounds good, I'll get those parts and just keep them on hand. I really want to know WHAT is causing the problem. I wish I had my fancy DMM or oscilloscope or something so I could check if there was actually an injector pulse on cylinder one. It had spark, but unplugging the injector did nothing.

 

I find it weird that the only way to fix the problem is to disconnect and reconnect the battery.