Im new to the forum and in need of some suggestions. I have listed all details of the car below. My problem is that Im having sputtering issues at full boost high rpm. I know that black smoke is somewhat normal but since this problem has started it is way worse. I have changed the plugs and checked cap motor and wires, all appears normal. I also replaced the head gasket due to a stuck thermostat which caused the upper radiator hose to blow. The car did not overheat as i shut it down immediately but for piece of mind i replaced head gasket and checked the head anyway. The sputter started prior to the thermostat incident. I also replaced the boost controller because my old one had a plastic housing and the threads became stripped so the boost was jumping all over the place. New one is aluminum. So I've checked everything i can think of. The fuel filter is also new but i am totally at a loss. Any help would be greatly appreciated. Also if anyone knows of a good tuner near Slidell/New Orleans Louisiana area that would be awesome too. My original tuner no longer does tuning. Again thanks for any and all suggestions.

97 EJ6
forged cp 8.5:1 pistons
forged eagle rods
bored and honed sleeves
.08mm overbore
arp head studs
arp block guard
golden eagle cam gear
hks cast iron manifold
tial 42mm external gate
770cc rc injectors
garrett gt28rr dual bb turbo
drag type 2 intercooler
aluminum ic piping
greddy oil catch can
blitz bov
single stage boost controller @ 16psi
tuned with uberdata chrome
stage3 comp clutch 4 puck race clutch
obx lsd
spoon sports aluminium strut tower
skunk 2 front upper control arms* (camber +/- 5 degree)
ground control coilovers
kyb gr2 struts
rota slipstream 15x7's

 

I had the same issue before. It turned out to be the coil inside the distributor, mine was starting to give out. If you can swap out distributors with a friends and see if the problem stops. That's how I was able to pin point mine to the coil being bad. I replaced my old oem coil with a Accel coil and haven't had any issues since then.