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Tim's Auto Repair
Tim's Auto Repair, mechanic
Category: Chevy
Satisfied Customers: 16035
Experience:  Have owned a repair shop for 25 yrs.
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2500 Sierra: 4x4..replaced the tps, Cap, rotor, wires, and fuel pump.

This answer was rated:

I have a 95 GMC 2500 Sierra 4x4. When I give it gas, it boggs down and dies ( over 1/2 throttle ). I have replaced the TPS, Cap, rotor, wires, and fuel pump. What is my next logical step?
is this a cfi[vortec] or a tbi engine?
Customer: replied 7 years ago.

It is a TBI. When I give it full throttle, you can watch the injector stream diminish as the the throttle plate opens. It will run and idle fine, and rev up with very little throttle, but if full open, it boggs out. I can manually add fuel ( with a spray bottle ) and it will rev up some more. It seems like it's starving for gas.

ok

check the fuel presure..this must have no less the 9psi at all times...the pump may be bad even if it is new...also make sure you install a new fuel filter,it may be clogged

thanks

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Testing and Inspection

NOTE: A fuel system pressure test is part of several of the Diagnostic Charts and Symptom Checks. To perform this test, follow this procedure:

FUEL PRESSURE TEST

  1. Turn engine OFF to relieve system pressure.
    • Disconnect negative battery terminal to avoid possible fuel discharge if an accidental attempt is made to start the engine.
    • Loosen fuel filler cap to relieve tank vapor pressure.
    • The constant bleed feature relieves fuel pump system pressure when the engine is turned "OFF".
  1. Uncouple fuel supply flexible hose in engine compartment. Install fuel pressure gauge between steel line and flexible hose.
  2. Tighten gauge in line to insure no leaks occur during testing.
  3. Connect negative battery terminal and START engine and observe fuel pressure reading. It should be 62-90 kPa (9-13 psi). If not, refer to DIAGNOSTIC CHARTS/FUEL SYSTEM PRESSURE TEST (CHART A-6).
  4. Turn engine OFF to relieve system pressure.
    • Disconnect negative battery terminal to avoid possible fuel discharge if an accidental attempt is made to start the engine.
    • Loosen fuel filler cap to relieve tank vapor pressure.
    • The constant bleed feature relieves fuel pump system pressure when the engine is turned "OFF".
  1. Remove fuel pressure gauge.
  2. Reinstall fuel line.
  3. Connect negative battery terminal and START engine and check for fuel leaks.
  4. Install air cleaner assembly.
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