1994 Mercedes Benz S420 hesitate

1994 MERCEDES BENZ S420
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WIDOWSON1
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  • 2 POSTS
Engine Performance problem
1994 Mercedes Benz S420 V8 Two Wheel Drive Automatic

sometimes while driving if i give it gas it will be hesitant like it want go then it will pick up speed doesnt do it all the time i change fuel filter and plugs wires are good
Sep 10, 2009 at 11:46 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
1994 Mercedes Benz S420 hesitate

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
Sep 10, 2009 at 12:24 PM
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