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Greg Audi A6 4.2

Greg ... 11/26/2011

2006 Audi A6 Quattro Base 8 Cyl 4.20L


The car hesitates i.e. engine lag and unless you feather the gas peddle its fall flat?

the car has 71,000 miles and recent service.

1 Answer


Jimm 11/26/2011

Possible Causes of Engine Hesitation or Stumble:

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


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