big problem
 

I have a 1987 supra turbo, mods are 2.5 inch inner cooler pipe, mbc 10psi, 3 inch full exhaust, adustable fuel regulator, no boost leaks for sure, foam air filter. Engine runs perfect, pulls ok under boost up untill I hit 5,000 rpm then the motor just starts back firing like crazy. I have a super monitor on the dash to check codes by pressing the buttons it will tell me the codes and the dash says, eng- ok. I don't know what to do. Am I crazy to think my foam filter is restricting air. Help me!!!!!!1

sure you're not hitting rev limiter (oddly enough) early?

is it fast backfiring or consistent or just all over the place?
what codes did you pull, in your post do you mean the codes were clear?

The wierd thing is that when my engine was all stock at 6 psi of boost, it never did it that bad from 5,000 rpm to six, it use to just pull very slowlly from 5 to 6 so thats why I think my foam filter might be the problem because since I'm running more psi now more air has to flow through my filter which is probably now restricting the air even more. I have completelly no codes existing in my diagnostics check.

I ran the car without the filter and I noticed a torque increase but still would cutout at 5,000 rpm. I remembered that I installed bosch platium spark plug and I did researh and learned that they are no good for turbos so I installed ngk plugs, i'll see what happens now.

well i ran it with new plugs and it still does it wtf!!!!!!!!!!!!

Next is to try to readjust the tps, thats all I can think of.

i think if it was the tps it would throw a code of some sort

can you describe the noise any better?

is it a slowish type cut or is it really fast?
is it the same cut as with the old plugs? or has the sound changed

have you had fuel cut off bypassed if not, if you exceed the psi on turbo more than 10 psi it will cut out so will have to get the ecu chipped to bypass

^ i'm confused

what has that got to do with his misfiring?

and just for future reference you can't "chip our ecu's" as such

fuel cut is not boost/psi referenced it is by hz which is what our afm measures and the hz frequency of fuel cut can vary it is generally between 11-13 for stockish vehicles and can be very low for high air flow vehicles

when i had my boost put to 15 psi i found when it got above 10 psi she would cut out and miss fire i had her chipped and has been runing sweet