i own a 2001 dodge ram van 1500 with a 3.9 litre engine 6 cylinder 6400 miles on her for the last 4 month the check engine light has been comming on my machenic puts his scanner on it and it comes back either misfire on cyl #5 or random misfires so i changed the distibuter cap rotor , plugs and wires it runs fine till i take it on the highway and the dam cel comes on as random misfires i am on my third distibuter cap no more cheap ones brass contacs where do i go from here thanks in advance arty

 

A lot of us have experienced that problem here. The engine management electronics could be causing trouble, or you could have another more serious problem like a vacuum leak or possibly a compression issue.

My CEL has been on for six months and I still can't track down my random misfire trouble. Another guy on this forum has changed every part he can think of, even those that have very little to do with a misfire issue, and his CEL is still on after many months (years?) without resolution.

This can be a tough problem to fix -- sorry I could not be more help.

 

I'm "the other guy."
I might have a clue to the cause of the problem. I have not fully verified it yet simply because I haven't had enough free time to get around to it. My #2 plug started misfiring like crazy and everything pointed to the injector leaking. I changed the injector which didn't solve the problem. So my attention went back to the spark plug with only 2500 miles on it. I took the plug out, which wasn't easy because the threads were carboned up. Once out I was able to test the plug and it worked perfectly. When trying to reinstall the plug I was having difficulty screwing it in. I took it back out and ran a spark plug thread chaser through the plug hole. After that I was able to spin the plug in with my finger. The #2 misfire is now gone. So my new theory is that the misfiring spark plug threads are carboned up and not making a good bond to ground. I am going to test this by removing all of the other 7 spark plugs and running the thread chaser through the plug holes to see if the misfires go away.

 

ok thanks guys for the advice.... i will pull out my new plugs and make sure they are fully threaded in and seated right it is worth a shot.... and i have been following your threads on this issue boy is it frustrating thanks arty

 

Hope you are on the right track . FWIW when I installed my new plugs in June of this year I did not feel any resistance while threading the plugs in. But, I did apply Never-Seez on the plug threads so that may have masked the feeling of any carbon build-up.

 

Maybe someone needs to invent a spark plug with two connections; one for the center electrode and one for ground?

Other than some changes in materials and electrode design the spark plug has remained basically unchanged for over 100 years.

 

I also hope this works for you, please keep us posted. And for some strange reason I though you have a V-6 instead of a V-8, lol.

 

Before jumping to conclusions, please take the time to read the V8 5.2L/5.9L ignition wire routing guide. This truly sounds like the problem here. Pop over to Geno's garage for the info.

 

i have a v6 3.9 i was very careful routing the wires and i added that snake wrapping over the whole lenth of my cables i plan on taking the plugs out one at a time and cleaning the threads this saturday i will let you know how i made out thanks arty

 

I took the plugs out and ran a thread chaser in each hole. The misfire count did drop by half, but it's still there. When I did the #2 cylinder the other day I also changed the spark plug but did not with the rest of them because I wanted to see if just cleaning the threads helped. So maybe I need to try new plugs too even though these aren't that old.

I do have the V6 3.9 engine.