Hey guys, I ran into a problem after a weekend of driving 500 highway miles and I was wondering if anyone else has run into this problem. The alti's got 108k on it and I threw in some fuel system cleaner in a full tank of gas before I left town.
Towards the end of the trip, I noticed some smoke particles/residue coming out of the exhaust under heavy acceleration ( ie. passing a semi )
Computer threw the code P0420 Catalyst System Efficiency Below Threshold about 3-4 days after the trip.
From what I found @ OBD-II Trouble Code: P0420 Catalyst System Efficiency Below Threshold (Bank 1)
A code P0420 may mean that one or more of the following has happened:
* Leaded fuel was used where unleaded was called for
* An oxygen sensor is not reading (functioning) properly
* The engine coolant temperature sensor is not working properly
* Damaged exhaust manifold / catalytic converter / exhaust pipe
* Retarded spark timing
Im thinking its just the O2 sensor picking up on the extra carbon being burnt off from using the fuel system cleaner or its just needs to be replaced after 108k? What do you guys think?