Mechanics

ROUGH IDLE.

2000 Chevrolet Silverado • V8 2WD Automatic • 150,000 miles

2000 Chevy Silverado 1500 5.3L 2wd. Has a rough idle and "Service engine soon" light. AutoZone gave me the following codes: "P0131" and "P0300." I have changed the plugs and wires, what's going on?

Also, there is a squeak that sounds like a belt when I first start the truck and sometimes continues, and sometimes doesn't (may or may not be related).

Also, the heat in the truck is not as hot as it used to be (once again, may or may not be related).
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Mcabee.duck
February 7, 2011.



The p0131 is 02 sensor, bank one. I can't say the sensor is faulty. I'd have to start by checking the wiring circuit.

P0300 is a random misfire, how long since a tune-up. Check the note below'


JDL
Feb 7, 2011.
As far as the heat issue, does the engine reach normal operating temp? Are the heater hoses hot? If you live in an area that is extremely cold, you may need to use a block heater.


JDL
Feb 7, 2011.
Thanks for the reply. Tune-up was done approx 1,000 miles ago. However, fuel filter has never been replaced. Would the o2 sensor code be caused by the random misfire (or vice versa)?


Tiny
Mcabee.duck
Feb 7, 2011.
The random misfire may have caused the other code.


JDL
Feb 7, 2011.
Ok, so what should I do to check the random misfire on random cylinders?


Tiny
Mcabee.duck
Feb 7, 2011.
Also, I believe the heat issue is related to a low coolant level. Thanks


Tiny
Mcabee.duck
Feb 7, 2011.
Below is the flow chart for p0300.


JDL
Feb 7, 2011.
I did see a couple of tsbs for that code. The possibilities are just about endless. One tsb was for a problem computer ground, G103 I believe. You take the ground loose, check the wiring, use a file or something and shine-up the contact surfaces. G103 is located, right rear of engine block. The other tsb was for water getting into the fuel system, caused by the evap harness, vacuum lines.


JDL
Feb 7, 2011.