I had someone suggest, to check my converter, to pull the o2 sensor out and that would relieve the backpressure that a clogged converter produces. So, if I take it out and power is restored that it is likely a clogged converter? right?

 

Very likely, but if a cat's insides broke up badly enough and went into the muffler then it could also get clogged (unless you have a straight through design muffler).

 

I think I'll have to try it and see. It's a 91' S-10 blazer with 170,000 mi on it and the cat and muffler are the originals I think. They both say GM or AC on them. I've "exhausted" every other idea. No codes and runs terrible

 

I would think that you can bang on the cat and muffler and hear stuff rattling around if they have fallen apart. You could also unhook your exhaust pipe at the flange and run it that way to see if it clears up your problem.

 

It has that mesh cover on it so when ya bang on it, it's hard to tell. I had a reman engine put in 3400mi ago and it's blown exhaust gaskets on both sides, and now one is leaking again. So, I have to assume i have restriction cause everything else is new.

Just took it for a testdrive without o2 sensor and the cat isn't the problem. I guess I need to go over the vacuum hoses again. If I pull the line off the intake and cover it with my thumb it seems to idle better. the only lines (I think) I didn't change where the ones going to the transfer case. I'm running out of options. Other than that the only thing I haven't changed is the battery. Had it tested, it came back 519cca and rated at 720cca. that wouldn't effect sensors or spark though would it? Alternater tested ok, changed it with a used one anyway, no difference. Did a fuel pressure test at the filter and it was right on spec. I've got 2 of everything (sensors) and nothing makes a difference.