1987 GMC Truck throttle/injector problems (please help)

MKENT3006

MEMBER
1987 GMC TRUCK
V8
4WD
AUTOMATIC
160,000 MILES

My truck will crank but when you to drive it, if you accelerate slowly it pulls ok, but if you mash it it just bogs down. It doesnt want to pull. Its absolutley not the trans. Its not the fuel filter. Its not the fuel pump. Injectors are new. Computer is new. Entire throttle body is clean. Only using one gas tank, its new, lines are new, tank switch is new also just cant figure it out. Please help

Sunday, December 20th, 2009 AT 5:20 PM

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Oxygen sensor
Catalytic converter
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

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Sunday, December 20th, 2009 AT 5:24 PM