Anyone else had this misfiring issue?

[Stinky]

Hello,
I apologize if this isn’t the right place to post this, but Im having an issue with misfiring on acceleration at 4500rpm+. Got new NGK coil packs 2 weeks ago and put new iridium step colder plugs in today (.026). It only seems to misfire after I’ve done one or two pulls, or if oil/coolant temps get above 170ish. I’m FBO, s280, HPFP and injectors, and I have a Mountune radiator so oil temps really dont ever get above 205. Have any of you dealt with a similar issue? I haven’t money shifted any time recently, but I have about 4 times in my 2 ish years of ownership (went 3-2 at 90 a few times).

 

[Jabbit]

Which cylinders misfire? Figure that out then swap coils and see if it follows.

 

[Stinky]

Which cylinders misfire? Figure that out then swap coils and see if it follows.

Im not sure, my accessport can only show me global misfire, not individual cylinders, and they’re all brand new coil packs, it doesn’t misfire at idle and it drives fine besides WOT.

 

[SteveS]

If it started after changing the coil packs, then suspect faulty coil pack. If it was running fine until you changed the spark plugs, then suspect the spark plugs. Try going back to OEM plugs.

 

[Stinky]

If it started after changing the coil packs, then suspect faulty coil pack. If it was running fine until you changed the spark plugs, then suspect the spark plugs. Try going back to OEM plugs.

Changing plugs didn’t help, and coil packs didn’t help either. I don’t think plugs or coils packs are the issue. I could try OEM plugs but when I first did my turbo upgrade I had the same type of plugs I do now, and I had no issues back then.

 

[SteveS]

Were the change of coil packs and plugs after or before the misfire problem? Hard to tell from your post whether they were things you threw at the problem which didn't solve it, or the potential causes of the problem.

 

[Stinky]

Were the change of coil packs and plugs after or before the misfire problem? Hard to tell from your post whether they were things you threw at the problem which didn't solve it, or the potential causes of the problem.

I’ve had this misfire for a couple months, and about two weeks ago I installed new coil packs and spark plugs. My negative corrections are typically not above -1, so I don’t think it’s bad fuel either. Just stumped as to what it could be.

 

[Stinky]

I’ve had this misfire for a couple months, and about two weeks ago I installed new coil packs and spark plugs. My negative corrections are typically not above -1, so I don’t think it’s bad fuel either. Just stumped as to what it could be.

And by above, I meant lower than -1, typically around -.5 to -.9

 

[TyphoonFiST]

Compression test findings?

 

[Intuit]

Does it misfire around that RPM, regardless of throttle input?

 

[Stinky]

Does it misfire around that RPM, regardless of throttle input?

No, only when I am at high/full boost, even half throttle will misfire.

 

[Stinky]

Compression test findings?

I havent done that yet, I should.

 

[Intuit]

Misses on hot engine, "high" RPM, at half-throttle or more. Reverted back to last "known good" settings with no impact.

What's AFR at 3500 RPM? Should read rich if missing at 4500 of course. Do the plugs appear rich, lean or just right?

 

[pshtal]

Currently going through the same exact thing , my next try is in tank fuel pump

 

[TyphoonFiST]

I havent done that yet, I should.

So did you remedy the situation and pressure check?