I have a 2000 chevy blazer LS 4x4 v6 4.3 vortec 163k miles.
New plugs & wires
New fuel filter
(other new parts i don't think apply in my situation.
I recently began to have acceleration problems. right at about 20 mph it seems as if im hitting a wall of air and it sometimes jerks if i give it too much gas. I attempted to disconnect my MAF and it seemed to help. so i went and bought a new one.. turned out it didn't work, so i returned it. I recently installed a new fuel filter. Didn't seem to help. My catalytic converter rattles and I think it may be bad. I've tried beating on it. My service engine soon light is also on. But i never get a code. no matter where i take it. I keep up on most maintenance. Lots of oil changes and coolant checking. Does anyone have a clue?

 

got a feeling its the cat also

 

yup, same thing literally just happened to me. much more power now

 

I was thinking cat before I even opened the thread!