1997 Chevy Astro Astro with a hesitatiion and backfires....

1997 CHEVROLET ASTRO
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TBREWED
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1997 Chevy Astro 6 cyl Two Wheel Drive Automatic

This is work van that has a really bad hesitation at take offs to the point I have to either pump the gas pedal or just floor it to go.

I've replaced the fuel pump and filter, plugs, wires, injectors, rotor and cap. I've actually replaced the cap twice which helps for a couple of days but gradually goes back to the way it was. Changed out the mass air and sensor which didnt do anything.

I'm at a complete loss now.....
Please help
Mar 15, 2009 at 11:00 PM
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RASMATAZ
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Hesitation could be caused by the following below

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
Mar 16, 2009 at 3:21 AM