96 k1500 5.7l missing on top end

my truck starts mission around 3500rpms in any gear tried fuel filter, cap rotor, tps, oem plugs, wires, coil pack, and put a fuel pump about 2 years ago.
cats are gutted  


fuel press is around 50psi at idle rev it up jumps to 60psi. while driving psi around 50 wide open jumps to 60psi then slowly comes down to around 52psi thats when it starts miss firing. im thinking the pump or the regulator. it is a napa pump.  

theres also an update for the injectors i saw in off road mag but i can remember the brand any help  

You have classic carbon build up in your combustion chamber and valves, top end.  Common in 5.7L engines up to 2000 year models, especially VORTEC design.  Need to get some Sea Foam from local auto parts store.  Treatment is easy, but depending on severity of carbon build up could take a few doses to get it all out.  For $20 to $30 (3 cans of Sea Foam) will cure it.  Buy one can of Seafoam deep creep and two cans of regular Sea Foam.

1. Use one can of regular Seafoam to treat your fuel system and crankcase (oil) per instruction on can.  Change oil and fuel filter soon after.

2. Use Sea Foam deep creep and spray it into throttle body as instructed on can.

3. Third Can of Regular Sea Foam.  Severe build up will require that you disconnect vaccuum line from brake booster with engine running at idle.  Engine will rev up to 2500 RPMs by itself.  Slowly pour 1/2 of third can into vaccuum hose; engine will be running rough and might stall.  Let sit for 5 to 15 minutes.  Drive and accelerate rapidly to blow the carbon out and thick white smoke from treatment.  Will cause quite a smoke screen and piss off neighbors. Repeat as necessary if you still have miss firing at that RPM range, but should clear up after all of this.  

Good luck.  This is how I cured this problem in my '99.  

You have classic carbon build up in your combustion chamber and valves, top end.  Common in 5.7L engines up to 2000 year models, especially VORTEC design.  Need to get some Sea Foam from local auto parts store.  Treatment is easy, but depending on severity of carbon build up could take a few doses to get it all out.  For $20 to $30 (3 cans of Sea Foam) will cure it.  Buy one can of Seafoam deep creep and two cans of regular Sea Foam.

1. Use one can of regular Seafoam to treat your fuel system and crankcase (oil) per instruction on can.  Change oil and fuel filter soon after.

2. Use Sea Foam deep creep and spray it into throttle body as instructed on can.

3. Third Can of Regular Sea Foam.  Severe build up will require that you disconnect vaccuum line from brake booster with engine running at idle.  Engine will rev up to 2500 RPMs by itself.  Slowly pour 1/2 of third can into vaccuum hose; engine will be running rough and might stall.  Let sit for 5 to 15 minutes.  Drive and accelerate rapidly to blow the carbon out and thick white smoke from treatment.  Will cause quite a smoke screen and piss off neighbors. Repeat as necessary if you still have miss firing at that RPM range, but should clear up after all of this.  

Good luck.  This is how I cured this problem in my '99.