Breakup 6k+ rpms

[cyhm]

Hey guys, so I've got this ignition breakup after 6k rpms and before I spent any more money throwing parts at the problem, I figured I'd ask for some opinions. The car runs and drives fine up until ~6k rpms. (I am on a 35r by the way.) I have replaced the plugs with bpr8es's gapped at .024" and the wires with ngk blues. (I doubt it's blow out because it ran fine with 6es's gapped at .027 before the issue came about.) As far as I could find there are no boost leaks, plus it breaks up in first gear as well as with the boost lowered. Wideband shows normal AFRs, if not, a little rich. (10.9-11.1 at times) I have not had the chance to datalog and check timing with dsmlink, etc. I don't have an available laptop at the moment.

I am assuming one of the coil packs is weak because 2 of the old plugs were fouled, but I didn't think to check if they were both on the same pack at the time. However, I have read that these coil packs rarely go bad and that there seems to be a laundry list of things that can cause this problem, but the 2 cylinders misfiring make me lean more toward something spark related. Therefore, I am wondering if there is anything else I can look for or test before spending money replacing good parts.

 

[007jimmy]

so you changed your spark plugs and wires and thats when the issue's started?

 

[kimba1666]

Mine had the same issue and the problem was fixed by replacing the intake manifold gasket.

 

[cyhm]

so you changed your spark plugs and wires and thats when the issue's started?

No. Sorry if I worded that funny. Made sense in my mind . I replaced them after the problem arose, but they were fine prior.... and probably still were fine seeing as though it didnt fix it .

Mine had the same issue and the problem was fixed by replacing the intake manifold gasket.

Hmm never would have thought of that. I do have a SMIM and noticed it's been kinda noisy lately, but wouldn't that throw off AFR's and/or have shown in a boost leak test? Also, did you only have 2 cylinders misfiring?

 

[ExtremeTurboSystems]

I would lean toward a coil going bad. I have had 2 cars do this to me. I think the reason it happened to me was the alternator was going bad and wasn't giving enough voltage to the coils. Replaced the coil and both times it has fixed the problem. If it isn't your coils I would check voltage under boost.

This is a good one too. What is your no lift to shift set to? is it 6k? because I have had the clutch switch go bad and it caused it to hit rev limiter because it thought the clutch was depressed.

 

[cyhm]

I would lean toward a coil going bad. I have had 2 cars do this to me. I think the reason it happened to me was the alternator was going bad and wasn't giving enough voltage to the coils. Replaced the coil and both times it has fixed the problem. If it isn't your coils I would check voltage under boost.

This is a good one too. What is your no lift to shift set to? is it 6k? because I have had the clutch switch go bad and it caused it to hit rev limiter because it thought the clutch was depressed.

The voltage according to my turbo timer seems to be ok. Consistent 13.5-14v. I don't have no lift set at all and my clutch switch is disabled actually. The car will run to my 8k limit, but it just misfires starting at 6k.