Ignition problem?

Haven't been on here in a while been kinda busy lately...Anyway since i never updated my sig, here's whats up.

97 GST hardtop
5spd
16g turbo (small)
Slowboy FMIC
NGK plugs
K&N FIPK
10.4mm wires
Hallman boost controller
Greddy Type S
ACT 2100
B&M Short throw

And new pics of the car - for you MySpace freaks. - http://profile.myspace.com/index.cfm?fuseaction=user.viewprofile&friendid=14406566

Here's the problem. A while ago, if i tried running 15+ psi, the car would start to sputter real bad. Of course, I tried fixing the complicated shit first. Turned out being my plugs. They were improperly gapped at .035 because when i first gapped them, i used a feeler gauge because i couldn't find my gapper lol...Anyway they're gapped at .028 now. I can run 17psi fine now, and it pulls like a champ. But here's the new problem. Anything over 17psi, the car starts to sputter like before. I'm not getting fuel cut. Yes I'm still on the stock fuel system and i know i'm getting close to maxing it out, but i was told by someone at the track that i should be able to run 19-20 with the stock fuel system. Is that true? And why is my car sputtering? Are the injectors starting to cut out but not completely?

i dont know about your injectors cutting out when i first finished my talon i could run 22 lbs before i hit fuel cut. when you hit fuel cut you will know it for sure. did you check for any leaks maybe you should do a compression test.

but it could very well be your fuel system i mean the last time i seen you your car had what 130,000 miles it could be time to replace that old ass fuel pump of yours you can run those injectors for a while just get a 190.

but i really dont know what else to say that just sounds like a wierd problem