Well I was driving the GTP last night, drove about an hour away, was running fine. When I was coming home, I took it easy for about 30 minutes, then coming onto the interstate I went WOT and it started missing bad, like it was only running on 5 cylinders. It continued to do this anytime the boost gauge would show anything over 1 bar. I got home and didn't even worry about it (it was 2 am). Came to work this morning, it was doing the same.

I'm thinking bad coil, what else should I check for? The only items I've replaced on the car are fuel pump, fuel filter, and plugs. I don't know any service records on the car up until I bought it, and it has 150k on the clock.

The first thing I think of from your description is O2 sensor and partially plugged cat. Of course I am probably way off...

I'd replace the Ignition Wires. What brand/type of plugs did you install. If they are not AC Delco, I'd replace them as well.

Could very well be the cat; Me and Bill boost had a similar problem recently. It would feel as if it was mising when the rpms were up and there was boost. Other wise there was just not enough air flow to casuse a problem. Here it was the catalyst had crack into about 4 peices and the honeycomb didn't line up straight enough for maximum flow.

Ed

The exhaust has been a little louder than usual lately, so I'll have to check it. How do you tell if a cat is bad??

The plugs were replaced with AC Delco of course.

My #6 plug wire caused the same problem. Got any codes?

No, I need to go get it scanned. I haven't been driving the car much lately and I keep forgetting.


If the cat is clogged, doesn't it get cherry red after you drive it for awhile, and would the car overheat??