Car wont rev WOT past 3500-4000 rpm

[svt_foci]

I have a 98 Cobra I will list the mods and the parts I have replaced below. Car won't rev past 3500-4000 rpm when at wide open throttle. I can ease it up well over that. Feels almost like the fuel cuts off or it falls flat on its face. Car ran fine until I changed the blower oil. I tightened up everything I loosened up but this is driving my crazy !!:mj: Any help would be appreciated! Thanks

Mods:
Pro Charger P1 @8psi/ 3 chamber Intercooler
42 lb injectors
90mm lightening MAF
Walboro 255lb in tank and Paxton external fuel pump
Anderson power pipe
Canton over flow tank
Tremec TKO600 spec stage 3 clutch
Alum fly wheel and Drive shaft
31 spline eaton locker
410's
welded tubes
Catless H pipe

What I have changed:
Alternator (was throwing p0340 code)
Cam position sensor
Plugs (ngk tr6 gapped to .032)
Ford racing plug wires
Ford Coil packs
Pulled the O2 sensors and tried to run the car just incase the sensors were bad but that didn't work either


Very well could be a boost leak but I cant track it down. If any one has any advise and how to find it please let me know.

Thanks

 

[deadernie]

Fuel pump not keeping up? I'd start by checking fuel pressure.

 

[Cowtown]

I'd check the fuel filter and pressure as suggested above. Do you run a blow off valve? When I ran a powerdyne back in the day that was always a spot where I would have leaks. Today it's much better with the parts they have, back then we had to fab crap to make things work. Anyways for me that was always a spot where I had to watch for leaks. Do you run a boost gauge as well, is it looking normal?

After all that is there a dyno/tuner than can hook it up and see what's happening with the car when it hits there?

 

[svt_foci]

I'll have to check the pressure and I bought a filter just not installed yet. Fuel pressure gauge took a crap so in the process of buying one to hook up

I do have a blow off. I'll have to check there too. My boost gauge reads fine but at this point I'm checking everything including vac leaks.

Thanks for the direction guys

 

[svt_foci]

Just thought it was weird that it was perfect until the blower oil change. I'm sure it's something simple. I just have to keep looking

 

[svt_foci]

Almost there I'm thinking. Hooked up Fuel pressure tester and read out at 20 psi. When revving the car psi would drop about half. Replaced the fuel filter and psi came up to around 26 and no drop off in psi after leaving the tester hooked up. Flow was light too no where near 1 qt in 30 seconds. Not right, but better. Looking at the Fuel pump next. Looks like I'm on the right path. Will update once I have a chance to complete the repair.