07 busa high rpm misfire?

[Ldb71]

Hey guys, I have a 07 motor in my legends car that I use for road racing. Last track day I had a weird problem that developed after the car sat for about 6 months. At about 7k rpm the engine would start making a popping sound almost like a misfire. Power still felt ok, air fuel ratios looked good. Checked leak down,, didn't fair well. Had cylinder head gone through (engine has 55k miles on it) problem has still persisted. I have now synced the throttle bodies they were a bit off. Still having the same breaking up sound. #1 and #3 spark plugs are a little more white on the electrode. Any ideas on what else to check?

 

[GMbusa]

Check the stator rotor key way on the crank. The key can break long ways and the rotor can twist on the crank causing a false rpm limit and misfire.

 

[GMbusa]

It happened to me

 

[GMbusa]

I spent 3 weeks searching it.

 

[turtlezx]

have you changed the plugs ?? usually breakup at high rpms

have a power commander?? if so add fuel

 

[Ldb71]

I have changed plugs, I have a power commander, have tried with and without the power commander

 

[JoeyL]

Having a similar problem on my 03, only at full throttle, will start stumbling after 8k.