I have a 91 b2600i, It was driving fine after a 80mile trip. Got home shut it off, 30min later I started it up to go somewhere and the engine was idling real bad up and down and just shaking horribly. I had my ecu repaired by avpro in FL last year because It wouldn't start. That cost me a lot truck was 6 hours away had to tow it back home. It would start from time to time. I recently went to the junk yard, pulled me a coil, module everything off that bracket that holds the coil in place. It started up, it seemed like a bad ground to me, i had a wire from the bracket to a good solid ground. It ran fine for about 30min. Now there is no spark again to the coil or wires. Question, would the main relay have anything to do with the inconsistant spark?? I also have an aftermarket cruise control unit installed on the truck from original owner. There is a blue wire that is connected to the coil wire (spade connector), which runs 5v. I'm not sure what this is for anyidea from anyone? Please help, i'm out of ideas!! Ithought aboutpicking up a new distributor buthow could it be the distributor if there is nospark from the coil?? Or is it possible that thesignal comes from the distributor to theignitor/module to the coil than back to thedistributor? Please help!!!! Thanks!!

 

i'm pretty sure thats how it works. the crank sensor is in the dist. so that sends a signal to the ecu or the ignitor to the coil then the spark goes to the dist.
the CC wire is probably just a rpm signal. do you have a CEL? find out if maybe you have a stored code.

 

spark module in the distributer maybe