Two OBD Codes...

[Matto]

Hi guys,

CEL came on recently in my Liberty and at the same time, engine began running sluggishly when cold/accelerating (then would gradually start running OK as I drove). Diagnosed the CEL and got the following:

P0300 (multiple cylinder misfire)
P0152 (O2 sensor shorted to voltage)

Anybody think these are related?

I already replaced all 6 spark plugs...running exactly the same. Any advice on what I should try next?

Thanks in advance--
Matt

 

[ltd02]

P0300 (multiple cylinder misfire)
P0152 (O2 sensor shorted to voltage)

What year and how many miles?

I'd check the wiring and connector to the passenger side precat sensor and see if it is okay. If it is okay, I'd change the sensor (use a Mopar) and hope for the best. Would be nice to get a scan and see what the fuel trims and sensor voltages are.

 

[Matto]

Thanks for the response.

2005 and approaching 80k miles. Again, not sure if these codes may be related. From the research I've done, the P0300 code doesn't tell us much....could be coil packs, wires, hose leaks, etc. Definitely not spark plugs as I changed all 6.

 

[SWilliams]

The misfires could be caused by the O2 sensor being faulty. It sends the wrong data to the ECM which alters the mix enough to cause the rough running.