2000 gmc jimmy loses power and backfires?

[Gary]

my 2000 jimmy has been backfiring and losing power if you get in it and try to just start it and go right away,usually if it idles for a minute its ok.today while i was driving it did the same thing and i couldn't get it to go over about 20...backfiring the whole time.any ideas...fuel filters and fuel pump have been replaced in the last year..it seems like the lower i am on fuel the worse the problem is.

 

[loves_me_chevy]

gm's are notorious for acting retarted when the gas level is under 1/4 tank.. have you tried fuel injector cleaner and doing a full tune up? that including distributor cap and rotor, spark plug wires, and spark plugs... it is also possible to have a tear in a fuel hose on the bottom of the vehicle that would not let the system pressure up the fuel line properly