Need help.. Rough idle/missfire

[1991KOTH]

Well.. Changed the spark plugs today hoping it would fix the woes I was having after starting the car about a week ago finding the rough idle but no dice. The plug in cylinder #7 was rough, so after changing all of them out and finding out it still was running rough i pulled the NEW plug out and there was oil on virtually half of the threads. I pulled another new plug on another cylinder to see if this was the case, but it didnt have the same issue.
Thats the new plug from #7 after removing it after starting it.

Here are all the old plugs:

Im kind of worried now.. Should I check the fuel system next or should I fear for the worst (piston ring)?


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[1991KOTH]

Keep in mind the idle is basically shaking the entire car.. Totally not normal and the engine seems to be "skipping" for lack of a better word


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[Demps]

With no knowledge of your car, I would next check the resistance across the coil packs (cold then hot if no symptoms). Ohm out the the mated wire ends to see if you have a coil problem.

Ted

[1991KOTH]

Originally Posted by Demps

With no knowledge of your car, I would next check the resistance across the coil packs (cold then hot if no symptoms). Ohm out the the mated wire ends to see if you have a coil problem.



Ted

Pulled each wire out while car was running. Pulling #2 and #7 did nothing. Gonna change coils and wires at the same time since Im pulling the plenum. Any suggestions for wires and coils?


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[Roadster]

Originally Posted by 1991KOTH

Pulled each wire out while car was running. Pulling #2 and #7 did nothing. Gonna change coils and wires at the same time since Im pulling the plenum. Any suggestions for wires and coils?


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I replaced my original coils with the MSD units #8224. You can also purchase AC Delco coils from vendors including Jerry's here on the forum. There are members here that use both brands.
There are also wires available for our engines. Hard to find a LT5 "script" wire set. But also the same wire is available without the LT5 "script". I did not change my wires when we did the pull a few months ago. That will probably happen in whenever!!!