Heres the situation: 01 A4 2.73
1/4 mile time @ trap speed, same track/prep/weather/time of year/tires, mods done each spring
Bone stock, 2002 Summer: 13.1 @ 106

Vararam, Stingers, Bassani x-pipe, no other changes at all, 1 year later: 13.4 @ 106

Vararam, Stingers, Bassani x-pipe, dynotune, 1 year later: 12.8 @ 109

Vararam, Stingers, Bassani x-pipe, same tune, MSD wires, TR55IX plugs with manufacturer's gap, 1 year later: 13.2 @ 104

My current setup: Vararam, Stingers, same tune, MSD wires, TR55IX plugs with manufacturer's gap, LG Pro Longtubes w/ hi-flow cats, 1 year later (this year, last week): 13.3 @ 106

No codes currently, had some codes when I did my header install and started the car without a boot on a plug for about 10 seconds by accident, but none ever came back on. I had the car on a Vantage scan tool and check everything before I went to the track, and only had one code: P0300: Engine Misfire. Misfires were in the 600-900 range three weeks ago when I checked. Today, when I checked again, my misfires were in the 1000-3200 range, but no misfire codes at all, and none happening while I was at idle. Only code was P0420. I understand this code dealing with my longtubes/cats, so I deleted it due to not having a new tune. I'm going to put it back on the Vantage tomorrow, so is there anything I should look for? I think I may have a very slight miss, but not sure. I just need some good advice guys and gals, whats going on with my car? I was just hoping for 12.6 @ 112 or so...

 

There should be ZERO misfires! PERIOD! If your having any indication of misfire,,,,you have a problem that needs to be solved before you go ANY further! Check the wires, plugs and coils. Could also have a bad valve or valve spring. Just a couple of thoughts!

Have you pulled each plug and checked the insulators for fowling or sings of misfireing?? Could also be acracked insulator on a plug! BEEN THERE!

BC

 

I have heard that MSD wires can come loose. I don't know how true this is,it"s just something I have heard. Also 12.8 isn't too bad for the mods you have. Could there be some driver errors?

 

Does it misfire right when you start it up, or does it take a few minutes to start misfiring?

 

I will be pulling the plugs and wires this weekend. I have the resistance specs for the wires, but haven't found the coil resistance specs yet using All Data. I'll try to pull the valve covers and take a look the springs if I have time. Thanks for the tips and info.

I've pushed on all the boots to make sure they were still seated, and everything checked good. I only launch a couple of different ways, not much to draggin an automatic . I was overjoyed to run 12.8 honestly, its just that I wanted to be a little bit faster after installing more proven mods . Thanks for the advice.


Hey is that you Kelly? Glad to see you up here, its been a while .
Nah, it doesn't misfire at startup or at idle. I've sat for 15 mins just watching on a Vantage and never saw one misfire. I'm gonna try to drive it down the road and try to record it misfiring hopefully over the weekend. Thanks for your input, I appreciate it. Oh, and when are you, Alvin, Qwinkle, and I gonna have a nice Vette Cruise ?

 

Oh Marcus, I didn't even realize that was you until I clicked on your profile and saw your car!

Did the misfires start after the headers? It's possible an o2 sensor may have gone south...can you see the readings with your scan tool?