Mechanics

I HAVE A CHEVY IT HAS A OBD2 CODE P0172 I HAVE REPLACED THE O2 SENSORS UPSTREAM OF THE CATALYTIC CONVERTER THE ENGINE SEEMS TO BE RUNNING VERY RICH, WHAT SHOULD I TRY NEXT? CLOSE TO CHRISTMAS CANT AFFORD TO KEEP THROWING MONEY AWAY.

1996 Chevrolet Tahoe • 145,000 miles

It has the 5.7 engine 4wheel drive
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Clayton barney
December 5, 2011.



Probable causes of an engine running rich are as follows: 1. Excessive fuel pressure can be cause by restricted fuel return line

2. Defective Oxygen Sensors.

3. Leaking injectors and fuel pressure regulator.

4. Coolant temperature sensor out of calibration.

5. Restricted air intake system.

Rasmataz
Dec 5, 2011.
Since you are only getting the code on one side of the truck I would concentrate on things that only effect that side of the engine and make sure you changed the correct sensor. (Driver's side)

Wrenchtech
Dec 5, 2011.