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Chipster 8/6/2012

2002 Mazda Protege LX 4 Cyl 2.0L


Why does my car hesitate when I step on the gas?

Car mileage-54,080 miles. I noticed a couple of days ago my car would hesitate when I stepped on the gas. Now the check engine light has come on and it seems like the engine will shut off when stopped at a red light or when I slow down then accelerate.

1 Answer


Jimm 8/6/2012

Possible Causes of Engine Hesitation or Stumble:

Dirty fuel injectors (cleaning the injectors often fixes this).
Dirty / clogged air filter element (change the air filter)
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


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