1999 Pontiac Grand Prix Slow Acceleration

Tiny
TEVANS318
  • MEMBER
  • 1999 PONTIAC GRAND PRIX
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 170,000 MILES
When coming from a complete stop my car takes forever to accelerate. I press the gas and it does nothing. It'll like ease into it very slowly. It so slow that somebody might hit me if I tried to pull out or something into the street. My car was flooded when we had bad whether. My fuel pump started going out earlier that day. After it got flooded I had the pump replaced and it started accelerating slowly but not as bad. Then I just got my computer replaced and its even worse. What could be the problem?
Monday, January 11th, 2010 AT 9:44 PM

1 Reply

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 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.
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Monday, January 11th, 2010 AT 9:49 PM

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