We are suspecting it has something to do with the gas.

1. It started to happen RIGHT after I filled up a new tank. Before filling up, car drove absolutely fine.

2. The misfire was really really bad that I could not even rev past 5k rpm. Once I filled up with new gas again, right away I was able to rev past 5k but there is still hesitation and misfire.

I just filled up a new tank and with a bottle of fuel system cleaner. If it doesn't help I will try to inspect and change the fuel filter, and maybe drain the gas tank completely and put in new gas.

 

I would check your injectors, it sounds like something is inside of them and is preventing proper flow, possible sticking closed sometimes or wide open....Check your fuel filter, fuel pump, and the little sock generally found on the pump and clean everything...You wouldnt believe the shit i found when i cleaned eveything. proper fuel delivery seems to be the problem

 

we don't have an easily accessible fuel filter on this car.

 

Here is a datalog of a few runs:

http://www.theblackmarkers.com/datalog.zip

Any help is greatly appreciated!

 

Going to check to see if the exhaust is clogged. Hopefully that solves it.

 

FIXED!!

CLOGGED CAT

My berk hi flow cat disintegrated.

 

so it was just choking up? interesting.

 

cat+fi=bad

 

Yes but po po + tow trunk + impound is even worse.

But there is a 70mm testpipe in there now..... back to shooting fireballs

 

I had misfire problems right after hard shifting.

and set of bkr8eix left at factory gap solved that.

And I'm running 18+ psi