I have been trying to figure out why my truck hasn't run right since I replaced Transmission. I changed every sensor, egr, distributor, did splices, and even replaced ecm but to no avail the truck still ran the same. It would start up nice and run smooth till it seamed to warm up then would pop, ping, backfire, and eventually quit running or never clear up. I finally took a break and did some research on other site to find a person with same problem and low and behold it turns out to be a mechanical problem not a electrical. I pulled off my brand new dist. cap to find the coil button chewed completely flat to the point of not touching. My original cap had a similar problem but not as drastic with it. Turns out my out the gear on my oil pump shaft had a spot on two teeth were chewed up and was causing it to jump and bang the button flat also causing my ignition problem. Also turns that these trucks have a problem with the brass bushing for the oil pump shaft going bad from the factory. So another $35. bucks and this should fix problem( Had to order so tomorrow is the day to see). Thanks to all that tried to help with info and parts and I hope this helps someone in the future.

 

Cool! Glad you got it figured out!

 

Good job. Someone will learn from this post.

 

Well I thought I fixed the monster but not the problem just another symptom. I now am not chewing up distributors but still not running right. I did some more poking around and located a post with same problems but different cause. They talked about intake plenum pan leaking after truck warms up so I took of intake and voila majority of the bolts were loose and when I remove pan you could see where oil was getting into intake. Now I am just waiting for the cash and will get new gaskets. This has been quite the project. Thanks for all the help and info. I sure hope this fixes it. On a funny note my wife pointed out she had saved all the receipts and I could sale this truck with a year warranty. LOL

 

Yeah I heard people having problems with their plenum's leaking on either the 318 or 360.(Can't remember) There was a post somewhere that told you how to test to see if you had the problem by doing a vacuum test before it got to the point you had. What year and engine do you have so we can have a heads up on that? Thanks

 

It's a 95 with a 3.9L. Well got money for parts and after I got home from work I tore into truck again. Bolted everything up and took it for a spin. Started of ruff till fuel system bled off air in lines and it seems like it cleared up so far. To early to tell but things look good so far.

 

Well I found something interesting after truck decided to do same thing as before, run fine cold then once warm it starts miss firing and back firing. I noticed a spot on firewall that looks like a spot to ground something. If anyone with a factory 95 3.9L Dakota could check theirs and see what it could be for, color of wire, and or where it goes. I think I think I have a photo uploaded to show what I am talking about. It is right above distributor.