I have a '93 F250, w/ 460 and 140k miles. Since purchasing the vehicle, I have noticed a definite change in performance. The truck now downshifts out of OD, while climbing hills where it previously had no problems. I have also noticed a change in its towing ability.

I have install a FIPK kit, and have been looking at a new catalytic converter and muffler. Am I looking in the right area? Is there a way to tell if my cat is really going bad, before I spend the $500?

Any help here would be great!
Thanks

 

A quality muffler shop can test the "cat" for you to see if its plugged.
At 140K miles your timing chain will definetly have slop and a computor sensor can be out of range without showing a computor error. The three sensors that affect your air/fuel ratio are the O-2 sensor, the air-charge sensor (ACT), and the engine coolant temperature sensor (ECT). I can't help you on the overdrive situation but I'm sure one of the other "regulars" can. Good luck, Deen