Coincidence or do you think there is a logical connection?
Mine will always throw a 420 whenever I drive slowly (usually in off-road conditions). Live reads show the rear sensor oscillating between 0.0 and 1.0 over and over so i'm gonna swap it out for a new one coming weekend.
Original only has 303,105 miles. :cowboy:
I think it's probably related. The ECM makes decisions about performance and tuning based on sensor input, TPS is critical as is MAF and MAP and O2/AF readings.
Another weird symptom, which was actually the first concerning one (besides occasional stalling at traffic signals after stopping) was falling out of cruise control with an RPM dive and recover. I assume that was also TPS-related because that has also not happened since swapping the TPS. The icing on the cake that made me swap the TPS was not being able to kick down and the inevitable TPS code, PO121
If you can see an exhaust sensor live-oscillating (output readings) then it's probably a good place to start, and I would have considered the same for my P0420 but my AF and O2 sensors are relatively new.
For the record, the symptoms/issues that I think were TPS-related (because they haven't come back since I swapped the TPS) are:
-stalling at traffic signals after stopping
-falling out of cruise control/rpm drop and recover
-low idle
-ac relay/clutch cycling with brakes applied (stopped at traffic signal in gear)
-inability to kickdown (eventually PO121 thrown)
If I think of any others I'll add them to the list