1999 Chevy Tahoe No power uphills

1999 CHEVROLET TAHOE

15,000 MILES • V8 • 4WD • AUTOMATIC

WOODSTER1

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I have a 99 Tahoe with 150k miles. It has been loosing power driving up steep hills. When it downshifts from over 2000RPM to a lower gear, it starts to shake and loose power. I have to drop it down to third gear to make it up the hill. If i don't drop it down one gear then the check engine light comes on and its a slow ride to the top. Can you guide me on the problem?

Dec 29, 2009 at 5:50 PM

RASMATAZ

CAR REPAIR CONTRIBUTOR
75,992 POSTS

Scan the computer for code/s could be something in there that relates to the tranny and also see below

Possible causes could be one of the following:

Oxygen 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
Coil and Rotor

Dec 29, 2009 at 6:12 PM

Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.