Code 55 is insignificant, it just means 'end of message'.
Use an OEM O2 sensor if you are replacing it. I have had problems with Bosch and 'Universal' O2 sensors.
Also use the correct Champion Copper Plus spark plugs listed on the underhood label for the vehicle. If this is a 2.5L, check the cap and rotor for wear.
Change the oil and filter as needed if the dipstick smells like gas.
Use an OEM O2 sensor if you are replacing it. I have had problems with Bosch and 'Universal' O2 sensors.
Also use the correct Champion Copper Plus spark plugs listed on the underhood label for the vehicle. If this is a 2.5L, check the cap and rotor for wear.
Change the oil and filter as needed if the dipstick smells like gas.