1995 Buick Regal Engine hesitation

DAVIDBUNKER

MEMBER
1995 BUICK REGAL
6 CYL
FWD
AUTOMATIC
135,000 MILES

My '95 Buick Regal Custom with a 3.8L V6 recently developed a hesitation or stumbling at around 40 MPH + or - 5 MPH while accelerating. I also had problems with the car starting, and the dealer replaced the ignition module, cam and crank sensors, and replaced intake manifold and rocker cover gaskets (they were leaking). The engine starts and runs fine, but the hesitation at 45MPH is still there. What are the possible causes of this hesitation?

Saturday, November 15th, 2008 AT 12:32 AM

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

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 coil
Wet plug wires

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Saturday, November 15th, 2008 AT 12:55 AM