Missfire at high RPM
Thread Starter
2nd Gear
Joined: Dec 2004
Posts: 2
Likes: 0
Missfire at high RPM
I just replaced my plugs and wires and now I have a missfire. It is s/c at 6psi. It was running fine with the old plugs and wires but the plugs where two years old. They where gaped at 35 but now there at 29 and didnt help. When i first put them in it ran fine intell the 5th run. This will be the 4th time taking them out and every time it looked fine. I did throw code p0172. I would think that would be because no spark to ignight the fuel. Im out of ideas please help.
Drifting
Joined: May 2004
Posts: 1,904
Likes: 2
From: London(UK)/Troyes(France)
Hi there,
I got that issue for over 6 months and after spending over $2000 on parts (plugs, wires, HP tuners, coils and labor) I came back to the plugs. I am SC as well, I installed a set of new NGK TR6 gapped at 0.35 at first. Then I tried 0.29, same issue. I made the gap even smaller just to try. Believe it or not the car ran fine for about 3 days. From that point I knew the plugs had a problem. I got a new set of NGK TR6 and gapped them at 0.29 from the beginning, it's been 3 months and the car runs great!!!
I just wanted to share my experience, in my case all the plugs must have had a problem. Good luck and keep us posted
I got that issue for over 6 months and after spending over $2000 on parts (plugs, wires, HP tuners, coils and labor) I came back to the plugs. I am SC as well, I installed a set of new NGK TR6 gapped at 0.35 at first. Then I tried 0.29, same issue. I made the gap even smaller just to try. Believe it or not the car ran fine for about 3 days. From that point I knew the plugs had a problem. I got a new set of NGK TR6 and gapped them at 0.29 from the beginning, it's been 3 months and the car runs great!!!
I just wanted to share my experience, in my case all the plugs must have had a problem. Good luck and keep us posted
Thread Starter
2nd Gear
Joined: Dec 2004
Posts: 2
Likes: 0
Thanks guys, I finally got it fixed. It was a combination of two things, last week I put some SeaFoam in the engine. I decided to pour the product through the brake vacuum line feeding enough to finally stall the engine. I then put the line back on and let the car sit a couple of hours. Next I start the car and fog for mosquitoes for the next 20 minutes. I noticed the car had an intermittent miss and decided to change plugs and wires which never fixed the problem. Today when checking for vacuum leaks we pulled the brake vacuum line when the car was running, the car stumbled and sputtered and started to spew white smoke from the exhaust. Two minutes later with the vacuum line reattached the car is running much better. It appears the Seafoam pooled in the vacuum line. At the same time we noticed as the car revved up the heat bag on the liquid intercooler would expand slightly. Turns out I had a small air leak near the intercooler coupling. Got that fixed and its running better than ever.
