hello there, hope this is the right place to post.
have a good friend who has a motor home with a 1994 494 chevy motor
, runs great on level ground, going up a hill of any kind at any altitude it bogs down. gas is fresh, fuel filer is new, taken to several garages who don't seem to know what to do. any sugestions? thank you in advance, juan

 

check for clogged exhaust eg.converter heat riser mud in rear off exhaust pipe