This is a repost of something I posted over at Allpar forums. trying to troubleshoot.

So, the last couple of days my 2bbl 318 in my 83 truck has been bucking (missing strongly). It does it sitting at stoplights warm or cold, and all the way through first gear when accelerating. it does not do it at higher RPMS, like say when cruising the highway or above 40 through town.

I replaced the spark plugs recently with stock AC Delco replacements, EXCEPT for one that is either really carboned up or crossthreaded. (maybe number six? next to the back on the passenger side). which I have yet to try to remove.

When I replaced them, I also replaced the wires, but not the cap and rotor. This is where it gets silly.

I decided that there was a possibility my buck was coming from a really burned cap and rotor...so today I got some replacements. Here's what I took off.






I've NEVER in all my wrenching seen a cap that badly corroded. The scary part? the top of the cap says "Mopar" with factory part numbers stamped on it.

PROBLEM: It still has the buck.

Do you think it could be that one plug? Something else maybe???

Thanks,
Ryan

 

I would say that plug is likely your problem.
Any dist. cap will get eroded over time, especially the original equipment with the aluminum contacts.
The replacements with brass contacts last longer.
I'm not a big fan of AC plugs either.
Especially in a Mopar.

 

i like the champion v-groove sparkplugs. i hate all those fancy sparkplugs that actually wear out quicker or don't work that great in a truck engine.

 

Use penetrating oil on that plug before removal. I would use penetrating oil everyday for 3-4 days before I put a wrench to it. I would also check the new cap and rotor after several hours of operation to make sure all that damage to the last ones was just corrosion and not any contact with each other. Another thing I would check is to open the hood at night with the engine running and inspect the plug wires for spark leakage.