Heres one for ya! My 98 1500 5.9 died at a stop light, no spark. Replaced coil, cap, rotor and cam sensor, still no spark. Went to Autozone and borrowed their OBDII and hooked it up to see what the problem might be, it showed no problems. I turned the key and the damn thing started! Ran great untill I unplugged the OBDII. Does anyone have an idea of what might be wrong? They want $575 for a ECM/PCM at the Dodge dealer, and said they never heard of such a thing! I'd rather buy the OBDII for $275 and leave it hooked up!

 

Sounds wierd. Check your relay for the coil. We had a Jeep (still a Chrysler product ) that wouldn;t spark. Replaced quite a few thing looking for the problem. It was the coil relay [&:] Maybe for some crazy reason when its hooked up to the comp it doesn't have to go through the realy, or something wierd like that. Worth a shot, just replace that relay with your horn relay and see if it works!