Low power - Engine or Transmission problem?

[Rosswp]

2002 F250 7.3 - Low power - meaning 30 MPH tops on a big hill and unable to climb up on a half foot of snow. Brought to stealership and they said giving P0420 code - and that the EBP and ICP sensors needed replacing (they wanted $700 to replace those sensors !!!!) I replaced the sensors myself but still same behavior. I changed the fuel filter and it seems like it is now more responsive to the throttle but still weak. I am wondering if it could be a slipping transmission or is it an actual low power problem. Any easy way to tell? Truck is new to me so I am not familiar with what it should feel like. I don't have a code reader yet, either. Any ideas? Help!!

[Mark Kovalsky]

It's easy to tell if the trans is slipping. Check the transmission dipstick. If the fluid is black and smelly the trans is slipping. If it's clean and red the trans is not slipping.

[Rosswp]

Checked trans fluid - I'd call it light reddish brown. Certainly more red than black.

[Rosswp]

Found the problem - whoever had this truck before for some reason cut the hose to the MAP sensor off. WOW what a difference.