Mechanics

CHEVY HESITATION UNDER LOAD

2000 Chevrolet Astro

Engine Mechanical problem
2000 Chevy Astro 6 cyl Two Wheel Drive Automatic 196322 miles

my 2000 chevy astro has serious hesitation problems when accelerating. I'ts had a full tune-up with no improvemt. The scanner shows misfire on cylinder #4 @ idle and misfire on all cylinders @ load. I've replaced the coil, fuel pump, spider web injector system and have had a compression test with the results of 180 lbs. Of pressure per cylinder, the MAF sensor is working fine. What am I missing? HELP PLEASE. Thanks, Terri
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Tunes1561
November 24, 2009.



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

Rasmataz
Nov 24, 2009.