1hotls1

iTrader: (6)

I recently installed a new set of NGK Iridium TR 55s, and all the old plugs looked fine except the one from #8 cylinder. It was fouled big time, but I was not having any symptoms of a misfire. After the swap out, I have begun to have a pretty good miss. It started out being barely noticeable, but is now getting worse. Although it did not trigger any codes, I had a friend try to read the computer for any misfires and it did not show any. However, when I cranked up to leave, the light came on and I had a lean condition code. While we were scanning the car, it seemed to show that the right bank was rich, but after this code, we plugged in again and right side was lean. Would a coil or plug wire problem on #8 cause all these problems? With my headers, working on that cylinder is hell. Any advice would be appreciated. I guess for now I'm going to go out and replace that plug wire and see how the car reacts.

TheBlurLS1

iTrader: (8)

I'd be very careful with the plugs/wires. If you have a cracked plug, it will arc out and not fire. It takes multiple misfires to setoff the SES light usually. Make damn sure all the plugs are seated well and the tips are screwed onto the plugs good (if you have older NGK's, they recently started using non-screw on tips).

If a cylinder is not firing, it's going to read lean because of all the unburnt air flowing to it. You have to remember that the sensor reads oxygen, not gasonline.

I went front regular TR-55's to IX's and noticed no difference in the behavior of the car.

1hotls1

iTrader: (6)

Thanks for clearing up my confusion on the O2s. I pulled #8 plug(less than a week in the car) and it was fouled much like the old one was. While I had it out, I cleaned it and replaced the MSD wire with the factory one. I've only run the car a few miles, but no missing yet! Is it possible that the wire was my problem, or is it more likely that there is something else like a bad coil or injector problem that is causing the fouling?

BobbyWS6

sometimes getting these wires off the back require a pretty hard pull in a direction that is not good for the plug wire. previous owner my have yanked the wire and caused some type of seperation. Running the stock wire is a good idea for a while. You are doing a good job of narrowing down the problem.

1hotls1

iTrader: (6)

Thanks for the encouraging words, but I just went on a drive and the miss is already starting to come back. The light came on again and its another lean code, so I guess the coil pack may be the culprit. Do any of you guys know if these coil packs can be firing yet not strong enough to burn the fuel? I know I have some spark at the end of the plug wire now, but I don't know if it is enough. The only other possibility for the plug to continue to foul out would be an injector dumping too much fuel I guess.