2001 Mercury Marquis low speed hesitation

2001 MERCURY MARQUIS
75,000 MILES • V8 • 2WD • AUTOMATIC
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JMCLAU74
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My 2001 Marquis hesitates while driving at slow speed,(35mph). When I accelerate it is fine. I don't need to hit passing gear to make the hesitation stop. I can just accelerate a small amount and the hesitation goes away. If I slow back down the hesitation comes back.

Thanks for your help!!
Oct 11, 2009 at 7:06 PM
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RASMATAZ
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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
Oct 11, 2009 at 8:07 PM