I've got a 6.0l truck that has started a habit of misfiring if you let it idle for more than 20 secs or so. Once it starts, it will eventually stop if you get above 40mph.

06 express 3500 6.0l
47,xxx miles

codes:

P0053: Unknown code - More information may be available on the web
P0132: O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)
P0135: O2 Sensor Heater Circuit (Bank 1 Sensor 1)
P0300: Random/Multiple Cylinder Misfire Detected

Freeze Frame data

Engine Load = 26.275 %
Engine Coolant Temperature = 75 °C
Fuel Trim Bank 1 Short Term = -35.156 % (do those look right?)
Fuel Trim Bank 1 Long Term = -19.531 %
Fuel Trim Bank 2 Short Term = 7.031 %
Fuel Trim Bank 2 Long Term = 3.906 %
Intake Manifold Pressure = 6.092 psi
Engine RPM = 647.25 rpm
Speed (OBD) = 27 km/h
Timing Advance = 16 °
Intake Air Temperature = 36 °
CMass Air Flow Rate = 74.438 cfm
Throttle Position(Manifold) = 0 %


From what I can gather, I need to:

Check for vac leaks
check the upstream driver side o2 sensor/wiring
possibly replace that sensor.

Anything else I should check, or be looking for.

 

Welcome to the forum. I think you're on the right track. I don't think there's vacuum leak, though. P0053 means heater resistance out of range on bank 1, sensor 1. It sounds like the sensor signal circuit is shorted high to the heater circuit. High sensor voltage translates to rich condition and thus the ECM reduced the the fuel on bank 1. Too little fuel then caused P0300, probably all on bank 1, i.e., odd numbered cylinders.

 

I changed the sensor today. Drove a couple miles and then let it idle for about 30 mins. So far so good.

Monday I'll probably find out for sure.

Thanks

 

So far, a week later, no misfiring, no codes.

Thanks

 

Congrats and thanks for the update.