Mechanics

A FLAT SPOT IN ACCELERATION

1990 Audi 80

Engine Performance problem
1990 Audi 80 4 cyl Two Wheel Drive Manual 96000 miles

i get a flat spot when the car is cold and accelerating in second and third gear but after about 200 metres it runs ok. New plugs and leads ok. And no oil or water leaks.
Avatar
Chuckle1
July 22, 2009.




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

Tiny
Rasmataz
Jul 22, 2009.


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