1998 Chevy Silverado High Speed Miss

CHEVYGEEK

MEMBER
1998 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
183,000 MILES

Engine Has miss when warmed up and running at highway speeds with RPM 1800 to 2800. Happens with cruise control on and off. Only happens when steady speed cruising. No miss at Idle or full throttle all the way to 5K rpm. No codes set. Fuel pump and fuel filter replaced. Local mechanic has no Ideas his diagnostic machine shows nothingother that start changing parts. O2 sensors [4] and TPS was changed no affect on miss. Any recommendations.

1 Reply

MATHIASO

MECHANIC
1,209 POSTS

Hello chevygeek

Probably one of the following sensors and or ignition components could cause the problem.
Check for 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)
and have fuel injector clean up.

Check also the ignition side such as dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
if there is no code, have it diagnose and look in "pending code"