97 Blazer 4X4 with 4.3 L V6 idles great but loses power on hills and wont run over 3,000rpm. Just changed fuel filter. Catalytic converter is noisy and i suspect this is the problem, but I would like a second opinion before spending hundreds of dollars.

 

I would suspect the cat but to be sure pull out the O2 sensor in front of the convertor and drive it down the road-up the hill without it. A cavemans way to do it but effective. If better-it's the convertor. jp[X(]

 

Sounds like what mine was doing. Check out the DIY forum by garry2000blazer
on cleaning MAF sensor. Its simple and cheap and works wonders. I thought it was cat on mine also, it had broken pieces in it so i cleaned it out but it didnt help it run better it just stopped the rattle. Good luck.