Random Misfire Under Boost

[mnetwork]

Well here is the story. I changed my lower intercooler pipe and had a new wastegate dump tube made. The person who did the welding on the dump tube kept screwing up and the coupler kept coming off of the lower i/c pipe. I just got under the car and fixed that myself. No leaks. And after I fixed it it's been misfiring ever since. I cannot say that it wasn't misfiring before the pipe came off because I never got a chance to do good pulls. I brought the car back to the shop and he changed the plugs and said it was running fine. On the way home it started misfiring again. It seems to do it under good load. When I do a hard 3rd gear pull and it randomly misfires in between 4.5k and high 5K. Just in case I tried richening it up on those ranges and A/F's dropped to low 10's, which is very rich for me, and it didn't do anything. The plugs are brand new, and the wires are good MSD wires just a few weeks over a year old. I just ordered both and they should be coming tomorrow. I don't see how changing those is going to help, but I'm going to try. What else should I be looking for??

 

[mnetwork]

Update: Well, got my new plugs and wires.. same as the ones in my profile.. Put them on.. did a bunch of pulls on the highway. Car pulls fine, no misfire at all. Don't know which one was at fault, the plugs or the wires, but the car runs fine now.

Very weird, because the plugs were new and the wires were only a year old...

 

[kenamond]

But the first time, you had someone else do the plugs? Did they gap them correctly? Might have been the gap was too big. You know what they say...if you want something done right, do it yourself.

 

[mnetwork]

I know.. I checked the plugs after I pulled them.. they were gapped fine.. Very weird problem, just happy this b/s is over...

 

[kenamond]

If you really want to know and still have the old wires, put them on. See if the miss comes back. If you have the plugs, you could swap them in, but wires are faster to change.

 

[mnetwork]

Yeah, I was thinking about it before... Too lazy to do it now, and it's too cold out to be standing in snow any more doing this, .