ok so... i finally have like $400 to use to attempt to fix this cars problem.

heres what its doin.

at and above 3500 rpms, if at a conciderable amount of throttle it backfires and sputters very badly, my assumption is its not getting the fuel it needs, or way to much air.
i can take it all the way up to 6k at part throttle and no problems at all.

things ive figured out/eliminated

tps-i can go WOT under 3500 and its fine, but above it its bad
intake vac leak-it pulls a good ~17 vac at idle, and vac is steady w. rpms
no valve float-vac guage has no jump to it or anything, very stable no matter what. and heads were just redone recently
spark problem-everything, coil, wires, cap, rotor, plugs are all no older then from january.
fuel press- at idle w. vac. it is at 30 psi, w. the vac dissconnected it is at 40, i ran it up to redline like that watching the guage, guage kept at 40, and prob. still happened.
MAP sensor is brand new

no related codes(just egr not opening), and balance test checks out ok

so lets hear wut yall think... i was gonna order a fuel pump and adj regulator, but fuel press seems to not be the problem

could it be injectors? how can i check that? i have no problem w. buying new ones, but wont spend $200 to just hope its the issue.

 

when you checked the fuel pressure... was the car under load up to 6k? or did you just rev it

 

How's the compression?
How's the fuel volume (different than pressure)

 

I agree.... If it was free reving that uses alot less feul than it would under a load. You may want to get a gauge you can watch wile driving the car. IMO 30 psi is a little low even with the vaccum hooked. You prolly already thought of the filter.

 

have the map replaced. brand new, might be faulty

 

no its just "free reving it", but even doing that you can still hear it happening. and the new map didnt fix it, so i swaped back to the stocker.

 

30 psi is low...

 

i agree 30 psi is low, however... it is in the stock specs(30-45) so it shouldnt cause problems w. the STOCK car.... one would assume

 

so it only backfires under WOT? exhaust backfire or intake

 

exhaust backfire... and i dont even no that backfire is the word.... its not like ur usual one loud BOOM, its a bunch of small pops, they can be heard from the exhaust. its not a backfire like fuel burning in the exhaust, its like not enough fuel burning in the cylinder

not nesacerally WOT, but at 3500 and above at a conciderable amount of throttle... half, no, 3/4 to full, yea