I've had problems with the ECU's going bad in my truck about every 2 years or so. They don't visibly show any problems but no spark. I had one go bad in Lowes parking lot with no warning and left me stranded. Shortly before that it would get heat soaked when parked and would create a no-start situation. Leave it sit for 3-4 hours and it would fire right up!

I've had to mess with making sure that they're grounded to the inner fender. Lose that ground and you'll get a no spark situation as well. My truck sits out in all kinds of weather so occasionally I'll rough up the back of the ecu and the fender mount locations with some sandpaper.

I've threatened more than once to put an MSD on the darned thing (since all my Mopar cars get them) and eliminate the ECU and ballast resistor but it's just a junky old truck.

Then again I HATE something that isn't stone reliable.