was doing some testing. I was at around 148mph + on a close course and I kept getting misfire.

That misfire wont let me go up all the way up to 150+MPH.

You think it's just the spark plugs or do you think it's something else, like ignition problems?

I get routine misfire all the time.

Thanks.

 

I'm not even gonna ask why you were running at insane speeds.

If your running stock intercooler you might be heat soaking the air coming in. This will take timing away and will make it fell like a missfire.

But if you have a missfire issue already then I would guess thats your prob.
Could be a lot of things :
Bad gas
Partially clogged injectors
restriction in the fuel system
Wrong inputs going in the ECU
ECT....

Or it could be as simple as Spark plugs.

 

When my plugs need changed they always misfire on topend.