1989 Chevy Silverado

1989 CHEVROLET SILVERADO
130,000 MILES • 6 CYL • 2WD • AUTOMATIC
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WINTER_HAWK
  • MEMBER
  • 1 POST
I have an 89 silverado with a 4.3 in it. When I first start it up it has a rough idle and also has severe hesitation when I try and take off. It will also backfire sometimes when it is hesitating. Once I have the engine up over about 2000 RPMs, it takes off, but at low RPMs, it acts like it is either flooding out, or starving for fuel. This does get somewhat better after it is warmed up, but it does not completely go away. I put in fuel filter, plugs, wires, rotor, & cap. STILL runs like a SHERMAN TANK. H.E.L.P.
Jan 15, 2010 at 3:03 PM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Check and test the following below:

Oygen Sensor
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
Cap and Rotor

Note:If it doesn't apply,disregard.
Jan 15, 2010 at 8:01 PM
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