sr20 problems

[sr20kouki]

ok here it goes, first of all my car has a redtop with a top mount precision turbo a custom intake manifold a power fc d-jetro those are the main mods, this all started about a month after i got it running,when i drive the car for a few minutes its fine i can beat on it all i want. then after a little while it sputters and cuts out but only when over 1/2 throttle and only in boost...(the throttle response is also getting worse)then i shut the car off for a few second and its fine for another minute or so...then it sputters again! ive changed coilpacks checked the plugs(perfect tan color) the tps sensor is fine i checked it three times..it was tuned twice by intec racing with no signs of anything bad...it has a few extra ground wires i made..im stumped, ANY advice would be awesome thanks guys

[nissanguy13]

Check your mafs, i/c piping and vaccum lines for leaks, and your idle air control valve. Are you running rich or have any black smoke? Out of curiosity did you ever run the engine stock or did you just now get it installed with all mods already done?

[sr20kouki]

it is a power fc d-jetro there is no mafs if it were a vacuum leak wouldnt it do it all the time and not just when it runs for a few minutes it was running fine in my friends d1 car it smells richer when it starts the sputtering but its not more black than usual, it doesnt have a idle air control valve

[Luvs2slide]

Check your plugs, timing, and maybe your tuning...

[nissanguy13]

not necessarily. I had a small vaccum leak. when I hit bumps or was woking on my engine I would hit something and my engine would sputter lose power, rpms would jump. Other times it would run just fine. You said someone tuned it. Did they check the cas? is your timing at 15 degrees?