Oldmobile bravada no power

I just took my 1994 old bravada into a shop to get it fixed because it wouldnt start they replaced the computer in it and now it runs but i still have no power up hill but will maintain speed but when i go up any hill it slows down afy anyone knows what is wrong with it or if this has happend to them please let me know what is wrong with it

Check/replace the fuel filter. Check fuel pressure and leakdown. Ignition on, engine off, fuel pump running, pressure must be 60 to 66psi. pressure must remain above 55 psi for 3 to 5 minutes after fuel pump shuts off. Post your results.

Possiblly could be plugged exhaust/ cat. converter

i just repalced the fuel pump before getting it fixed but it could be the pressure and how would i fix it if it is not at the right pressure would there be a leak somewhere or what?

See post #2 and post your results.

i turned the key to the on possition and the fuel pump ran for about 10 seconds and never came back on i dont know if it should come back on or not

When the ignition switch is first turned to the RUN position, the fuel pump should run for approximately 2 to 3 seconds and then shut off. When the ignition switch is turned to the START position, the pump should run continously. After the engine is running, the pump should run continously. If the engine stalls, the pump will shut off approximately 2 to 10 seconds after it stalls.

when i turn the key to the run position the fuel pump ran for about 10 seconds and when i started it it ran all the time but i never heard it cut out