2002 Chevy Malibu 2002 malibu hesitation on acceleration

2002 CHEVROLET MALIBU
60,000 MILES • 6 CYL • FWD • AUTOMATIC
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LEMIEUXSTEVE
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I have a 2002 malibu that hesitates upon acceleration up to about 30 mph. I have had a tune up recently (or at least the mechanic told me so) and it didn't seem to make a difference. What is the most common casuse of this?
Jul 18, 2008 at 12:17 PM
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RASMATAZ
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Possible Causes of Engine Hesitation

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
Jul 18, 2008 at 12:21 PM
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LEMIEUXSTEVE
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I located the sales receipt from the tune-up. It states that the work done was:

Engine diagnostic
Fuel injection/mass Air Cleaning
Flow and throttle body decarbon
Fuel filter replace

What should I check now? Could it be the catalytic converter? Should I try spark plugs first?
Jul 18, 2008 at 8:14 PM
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RASMATAZ
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Should I try spark plugs first? Do so and check the fuel pressure and the throttle position sensor
Jul 19, 2008 at 1:15 PM
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LEMIEUXSTEVE
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It was the catalytic converter. Still covered under the warranty. Nothing beats free. I saw people (online) had the same problem and payed for it, my only advice is check with a dealer or your warranty.
Jul 31, 2008 at 11:16 AM