Loosing Power Fast

[Danbo2003]

hey guys me again i have a 2003 gmc sonoma zr 2 4 x 4 v6 ihave had a rattle under the truck for about a week now thought it was the heat sheild on the catalytic converter yesterday well driving to vt i was going up a hill and the truck kept loosing power the more i put the pedal to the floor the less power i had and the more the motor would rev i could also hear a lot of rattle and pinging today i took the truck for a spin and it is just as bad if not worse.... im hopeing that it is the cat and not the trans...any more advice thank you alll....

[8.1HD/ALLISON]

Could be the cat comming apart. Check the backpressure.

[GMstrong]

ive heard of a clogged cat causing loss power.

[kmborland]

my jimmy did that to me about a month after i bought it. the cat was bad so i got a custom fit cat from lmc. i had not power at all! just a very nasty sounding v6(meaning it just didnt sound good)