1993 Chevy Suburban Hesitation

SUBURBANGUY

MEMBER
1993 CHEVROLET SUBURBAN
V8
4WD
AUTOMATIC
207,000 MILES

I have a 1993 Suburban that I have virtually replace everything I can think of that would cause this hesitation. It seems to do it when it is up to operating temp. The kicker about that is it doesn't do it all of the time. It bucks and hesitates like it isn't getting enough gas or maybe too much. I have replaced the tank, fuel pump, sending unit, filter, rebuilt the fuel regulator, cap, plugs, rotor, wires, EGR valve and coil. There doesn't seem to be any vacuum leaks that I can find. I know the gas cap leaks but would that cause it to be intermittent?

Wednesday, January 21st, 2009 AT 8:30 AM

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Hesitation could be caused by the following:

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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Wednesday, January 21st, 2009 AT 9:01 AM