1996 GMC Sierra 5.0 Acceleration

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Vitals. C-1500 2 wheel drive, auto, air, 5.0 engine with approximately 150,000 miles. Cared for extremely well. Consider this vehicle babied!

During acceleration truck hesitates badly. It does not backfire, or misfire, but it is slow to rev up. Say your cruising at 45mph at 1900 RPM and you try to accelerate the engine will rev up to 3000 RPM's, but the vehicle will not go faster, it will just stay at 3000RPM's. The car will throw a code for the MAF. I have replaced three MAF's, and one thermo temp sensor. NO help. By mistake I realized that when I disconnected the MAF, and Temp sensor, and keep the MAF and temp sensor disconnected the vehicle would accelerate, and run better, but not like new, or how it should. I have checked the fuel pressure, and it is 55 psi.

1. Transmission completely overhauled.
2. Recent tune up (cap, rotor, wires, plugs, oil and filter)
3. Today I changed 4 O2 sensors, TPS, Idle Valve, Ignition coil, and module.
4. I also checked the EGR, and engine wires.
5. Put gun to head, and tried shooting, but gun misfired also!
6. Read engine codes with OBD II, and it throws two codes. One is for O2 sensor (which was replaced), and the other is for ignition high voltage, (which coil, and all other items concerning ignition were replaced).

Feel free to post or email me. I really need the help.

Any help would be very grateful!

posted by  Anteupfred

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