High base fuel pressure, 6k rpm stutter

[colerongo]

ok so my car is a 1999 eclipse gsx with a 6 bolt swap and an auto to manual swap. everything is pretty much stock including injectors, fuel pump(new oem replacement). I do have a fuelab afpr.
I just started this project this spring. Since i got it running a few months ago it has had some issues (seems to be a fuel problem). the engine revs smoothly all the way up to about 6k rpms, then it begins to stutter (possibly fuel cut?).
the way i have it set up now is 50psi of base fuel pressure with the vacuum line connected. I understand that this is high but any lower and stuttering begins sooner in the rpm range and feels more severe.
am i running rich or lean? could my fuel pump be leaking off pressure at the tank? i dont have a fuel gauge in cab so i cant monitor pressure as i drive. could a boost leak cause this? i did a boost leak test when i first got the car running and fixed all the leaks i found.
any ideas on what this may be or of how to go about finding the problem would be appreciated. thanks

 

[DSMsamurai666]

It sounds like a fuel trim problem I was having when my MAF translator went hay wire and made the a/f ratio way too rich. I would say that either your fuel pressure is too high or perhaps something has gone awry with your MAF. It could be your intake air temp sensor. I would start by getting a proper a/f/ gauge to make sure that's the problem.

 

[LiquidX]

How long has this been going on for? Did you check your plug color at all?

 

[colerongo]

it has been doing this since i got the 6bolt swap started a few months ago. i haven't been driving the car much though because i am in school at a maritime academy and cant leave campus.
i just replaced the plugs because i wanted to make sure they were new and good since the others were used during the swap/getting car started stage. the old plugs were white (looked lean to me) on the tips, and black (looked rich and covered with fuel residue) on the outsides where the threads start but are exposed to the cylinders. seems strange to me.
i am pretty sure that my car does not have an intake temperature sensor, unless it is inside the MAF. my car still runs with the MAF disconnected. in fact, i remember it not even changing the idle when i disconected it while it was running. maybe this is my problem. how could i know for sure without having a working one available to test out?
thank you for the help so far, keep the ideas coming, i need the help

 

[colerongo]

i think i should also mention that i have not been in any other 4g63 powered cars, but this one still seems pretty powerful and quick considering everything is mostly stock. Before this car i was into datsun 240z's with inline 6 turbo motors. My GSX is stuttering at high rpm's but still pulls pretty strong until that point. just thought i'd throw that out there.
also, i know the fuel pressure is too high, but it runs worse when i turn it down to spec.