Car breaks up at high RPMs but only in higher gears

[RMeadows]

Could this still be a problem with the spark plugs being blown out, or would a spark plug problem happen in every gear?

Basically the car starts stuttering and backfiring in 3rd gear and above when I get over 5K RPMs. If I stay on the throttle the car will keep trying to pull but it will begin to knock. Car has no boost leaks and I have plenty of fuel.

 

[hereitcomes]

Could be a rich/lean issue. Are you using a datalogger? I spark problem would usually happen in every gear, and not necessarily be noticed. Your car will act fine essentially, but you can melt your plugs. I suggest consulting a logger. Post back good luck dude!

 

[CanadianTSi]

New plugs gapped at .028 is always a good idea.

 

[95blackGsTurbo]

Plugs can be picky. When mine went they would only miss once and a while when the car was warmed up. They would be the first thing I would look at just because they are the cheapest/easiest to replace.

 

[RMeadows]

Well, I played with my MAFT and AFPR a bit and I seem to have gotten rid of the problem. I did log the car however so if you guys wanna take a look and make some suggestions i'm all for it. Especially with regards to that slight bit of knock. This was only at 15 pounds on an EVO3 16G.

TIMA,,,,, COOL,,,,, O2-R,,,,, TPS,,,, MAFS,,,,,, RPM,,,,,,,,,, KNCK,,, INJP,,,, INJD
37.00º, 96.88ºC 0.35V,,,,23.14%,81.77Hz,,2093.75rpm,0.00,2.56ms,5.00
31.00º, 96.88ºC, 0.88V,,,,24.31%,125.80Hz,,2156.25rpm,0.00,2.82ms,6.00
29.00º, 96.88ºC, 0.90V,,,,24.71%,132.09Hz,,2187.50rpm,0.00,2.82ms,6.00
29.00º, 96.88ºC, 0.70V,,,,24.71%,132.09Hz,,2250.00rpm,0.00,2.82ms,6.00
30.00º, 96.88ºC, 0.10V,,,,25.10%,138.38Hz,,2281.25rpm,0.00,2.82ms,6.00
30.00º, 96.88ºC, 0.82V,,,,25.10%,138.38Hz,,2312.50rpm,0.00,2.82ms,6.00
30.00º, 96.88ºC, 0.10V,,,,25.10%,144.67Hz,,2375.00rpm,0.00,2.82ms,7.00
30.00º, 96.88ºC, 0.86V,,,,25.49%,144.67Hz,,2406.25rpm,0.00,2.82ms,7.00
30.00º, 96.88ºC, 0.86V,,,,99.22%,188.70Hz,,2500.00rpm,0.00,4.35ms,11.00
28.00º, 96.88ºC, 0.92V,,,,100.00%,201.28Hz,,2593.75rpm,0.00,4.35ms,12.00
27.00º, 96.88ºC, 0.92V,,,,100.00%,207.57Hz,,2718.75rpm,0.00,4.35ms,12.00
28.00º, 96.88ºC, 0.88V,,,,100.00%,239.02Hz,,2781.25rpm,0.00,4.61ms,13.00
27.00º, 96.88ºC, 0.88V,,,,100.00%,264.18Hz,,2906.25rpm,0.00,5.38ms,16.00
26.00º, 96.88ºC, 0.92V,,,,100.00%,308.21Hz,,3062.50rpm,0.00,6.14ms,20.00
24.00º, 96.88ºC, 0.94V,,,,100.00%,371.11Hz,,3250.00rpm,0.00,7.42ms,25.00
20.00º, 96.88ºC, 0.94V,,,,100.00%,490.62Hz,,3437.50rpm,0.00,9.22ms,33.00
15.00º, 96.88ºC, 0.94V,,,,100.00%,578.68Hz,,3687.50rpm,4.00,9.73ms,38.00
14.00º, 96.88ºC, 0.94V,,,,100.00%,641.58Hz,,3937.50rpm,3.00,9.73ms,40.00
15.00º, 96.88ºC, 0.94V,,,,100.00%,679.32Hz,,4125.00rpm,9.00,9.73ms,42.00
12.00º, 96.88ºC, 0.94V,,,,100.00%,748.51Hz,,4343.75rpm,8.00,10.24ms,47.00
12.00º, 96.88ºC, 0.94V,,,,100.00%,817.70Hz,,4625.00rpm,7.00,10.75ms,53.00
12.00º, 96.88ºC, 0.94V,,,,100.00%,893.18Hz,,4781.25rpm,5.00,11.01ms,56.00
13.00º, 96.88ºC, 0.94V,,,,100.00%,937.21Hz,,4968.75rpm,4.00,11.26ms,59.00
12.00º, 96.88ºC, 0.94V,,,,100.00%,1006.40Hz,,5187.50rpm,3.00,11.26ms,62.00
14.00º, 96.88ºC, 0.94V,,,,100.00%,1063.01Hz,,5437.50rpm,3.00,11.52ms,66.00
15.00º, 96.88ºC, 0.94V,,,,100.00%,1081.88Hz,,5562.50rpm,2.00,11.78ms,69.00
15.00º, 96.88ºC, 0.94V,,,,100.00%,1163.65Hz,,5718.75rpm,1.00,11.78ms,71.00
16.00º, 96.88ºC, 0.94V,,,,100.00%,1163.65Hz,,6000.00rpm,2.00,11.78ms,75.00
16.00º, 96.88ºC, 0.94V,,,,100.00%,1213.97Hz,,6125.00rpm,1.00,11.78ms,77.00

 

[95blackGsTurbo]

Looks good but running a little rich. I had a problem with a studder in higher gears when I was running too rich. Looks good and consistant otherwise.

 

[RMeadows]

Looks good but running a little rich. I had a problem with a studder in higher gears when I was running too rich. Looks good and consistant otherwise.

Yea, I guess running too rich is causing that knock. I haven't yet switched over to fine tuning mode on the MAFT. Guess I will have to now though. I don't have any way to take out just a little bit of fuel at those rpms otherwise.

thanks for the replies