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p0302 Cylinder 2 Misfiring, weird rubber ring on plug?

5379 Views 7 Replies 6 Participants Last post by  whynotthinkwhynot
Hi Fanatics,

This is my first post, having an issue with my wife's '04 SVT, only mods are a drop-in K&N air filter and Tom's Tune that was loaded about 6 weeks ago. According to my wife yesterday the car started sputtering and bogging, she thinks it was somewhere in the middle of the rpms and at mid-throttle. She got home and had a p0302 CEL for mis-firing in cylinder 2.

To see if it was anything with the tune I switched back to stock and the problem remained. From what I could find the typical causes are usually ignition related so I pulled the plug wires and plugs to check, I've attached some pictures of them, in the picture they are in order with cylinders 1-4 from left to right. The wires seem ok and the plugs look pretty much the same across all of them, but I'm not very confident that I can read the plugs correctly. Strangely the rubber ring around the middle of the one from cylinder 2 was on it when it came out, I guess maybe it's part of the plug wire but can't see where it should have been. Please check out the pics and tell me what the rubber ring is/means. From that I'm thinking plug wires and plugs as well if needed, but if you wise and experienced folks have any advice I'd really appreciate it.

Also, I've read on here that the coil is often the culprit, haven't checked that yet but I'll take a look when I get home and try swapping the plug wires to see if the problem moves to a new cylinder. To diagnose misfiring in cylinder 2 I should swap plug wires 2 and 3 on the coil to see if the problem moves to cylinder 3, correct?


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Then a waste of time putting them back in. The rust belt around bottom of the porcelain says the spark could possibly be leaking down outside of plug to short to the outside lower metal case. These are bad about that.

The only way you can check plug wires is by the resistance per foot of wire, or 5000 ohm per foot and no more. You need a cheap voltmeter for that, Harbor Freight was giving them away free last week if you bought anything at all.
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