OK here goes, 2000 Grand Cherokee Limited 4.7is throwing a 420 code. The reader says now its bank 1, that is the front ones right?
Corrected the cyl 5 misfire it had for forever. now looking to finish clearing my check engine light for good.

 

Still looking for an answer.

 

Bank one should be on drivers side. Youll need to check your o2 system sensors and wiring and check your catalytic converter.

 

update
Wife took the Jeep on a 350 mile drive towing a empty u-haul trailer. About halfway there She noticed the rear brakes were smoking. The front were replaced 3 months ago for the same reason, the calipers were not releasing correctly.
They do a parking lot repair, and now the check engine light is off, it shifts perfectly. Even after towing a full trailer back that 150 miles.
Goes to show you never really know what is wrong with a Jeep.