HELP.. PO 0300 Code 2002 Chevy Silverado 5.3
#1
HELP.. PO 0300 Code 2002 Chevy Silverado 5.3
Random Multiple Cylinder Misfire Trouble
Already Replaced:
Plug & Wires
Mass Air Flow Sensor
Cam Position Sensor
Crankshaft Position Sensor
and checked for vacuum leaks..
Before replacing all this i had a lean code and the multiple misfire code (PO 0300)..now it just has a misfire code (PO 0300) and still a bad skip...
seems to be worse when cold. Please help, i've been banging my head against the wall with this one!
Already Replaced:
Plug & Wires
Mass Air Flow Sensor
Cam Position Sensor
Crankshaft Position Sensor
and checked for vacuum leaks..
Before replacing all this i had a lean code and the multiple misfire code (PO 0300)..now it just has a misfire code (PO 0300) and still a bad skip...
seems to be worse when cold. Please help, i've been banging my head against the wall with this one!
#6
The PCM will usually detect anomalous O2 sensor readings and set a trouble code. However, an O2 sensor can go out of calibration (hard to test for that) or an exhaust leak can affect its measurements (oxygen content inside the exhaust pipe vs. outside). If you have anything aftermarket in the intake or exhaust system, or PCM tune, start your troubleshooting there.
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#8
If you've measured it with key on, engine off, it should be 55-62 psi. If so, suspect the fuel pump or fuel pressure regulator. If you can raise the pressure by repeatedly priming the fuel system (turn the key on, wait a few until the fuel pump cuts out, turn the key off for a few, and then repeat), it'll usually mean a fuel pump on its way out. Note "usually" rather than "always."
#9
Ok, today out of desperation i changed the intake gasket because someone at the parts store told me they had a similar problem and that fixed there truck so i went for it and STILL NO FIX Grrrr...
Did another fuel pressure test and with the key on and the engine OFF ive got 50-52 lbs but with the engine running its about 47 lbs. What do you think??
Did another fuel pressure test and with the key on and the engine OFF ive got 50-52 lbs but with the engine running its about 47 lbs. What do you think??