Mechanics

CHEVY WON'T GO OVER 40 MPH

1999 Chevrolet Silverado

Engine Performance problem
1999 Chevy Silverado V8 Four Wheel Drive Automatic 180000 miles

The truck won't go over 40 mph. It does seem to be shifting normally so I don't think it is a trans. Issue. When the codes were checked, 02 sensors came up but nothing else. Do you think it is the Catalytic converter?
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Jpeter741
January 16, 2010.



Check and test the following below: Oygen Sensor
Catalytic Converter
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
Cap and Rotor

Note: If it doesn't apply, disregard.

Rasmataz
Jan 16, 2010.