no power half-full throttle

[Just me]

Hey all. My car is sputtering under half-full throttle. I mash the gas pedal and it feels like I'm only on 6 cylinders.When I look at my fuel pressure gauge during idle, the needle shivers between 38-43. I increased and decreased the fuel pressure to no avail. The car idles like a champ, firing on all 8 cylinders. What should I look for and how can I test it? Should I do a compression test for a blown head gasket. I see no tell tale signs of one but I have a gut feeling. Well I'm not ruling out anything such as, mass air, o2 sensors or egr. Help?
Thanks

Just me
91'lx, 302 block, crank pulley, no smog, short belt, Wolverine 1087 cam, 15 deg timing, TFS TW heads, motorsport 1.6 3/8 stud RR, ARP studs, TFS chrome hardened push rods, 24lb inj, BBK 255lph fuel pump, Areomotive billet adj FPR, Performer RPM intake(ported to 75mm), 1" spacer, Motorsport polished tall valve covers(love em), Pro-M 77, Acufab 75mm TB, Ford idle air bypass valve, K&N conical, MSD 6AL and coil, 9mm MS cables, NGK bkr5e 11 plugs@55, motorsport 3 core radiator,160 thermostat, Hurst short throw, motorsport 410 gears, aluminum drive shaft,Kenny brown Subs, Mac 1 3/4"Long tube, custom 3"off road xpipe, 2 chamber Flow Masters, 3 1/2" tailpipes HAL tubular K-member, KYB struts and shocks, Eibach springs, Steeda 2.5" Cowl, Steeda rear wing, black Dupont centari acrylic enamel paint.