I have a 2004 F150 4x4 with a 5.4 engine and currently only 64K miles on it. I believe the catalytic converter(s) may be failing as I notice a loss of power while accelerating when towing and am beginning to smell a burning plastic or rubber smell. Anybody know if there is a factory warranty on the cats since so low mileage and if not how much will this cost me to repair? Thanks everybody!

 

8 years or 80k miles. California cats are quite expensive.

 

California cat warranty is 7/70, federal is 8/80. In any event, the OP is SOL regarding any converter warranty since it's a model year that's 13 years old.

Suggest the OP have the system properly diagnosed instead of only guessing. Saves a lot of angst.