Im having prob with the motor stumbling but never dying and it seems short on power thinkn it might be the cat if i took it off and knocked the guts out to clear the pathway would it jack up my o2 sensors ???

 

most likely

 

I'm sure it'll trigger the post cat sensor if yours has one, not sure about the other ones.

Speaking of O2 sensors, you can remove one or both of your precat sensors and see if it runs better, if so, it's probably a clogged cat. I had to do this a couple of years ago, 100 miles from home pulling a camper up a mountain.

 

i might try that im running out of options the only thing left is o2 sensors maf or cat

 

Only the downstream sensor, (the one behind the converter) will be affected.** The service engine soon light will remain on as soon as the monitor runs and completes the converter test. The safe way to check for an exhaust restriction is to install a pressure gauge in one of the upstream oxygen sensor bungs. More than .5psi is a problem. An alternate method is to remove the two upstream sensors, take it for a short drive and see if performance changes. Be aware that the exhaust it hot, and you might need to install a temporary heat shield to avoid things getting hot, that shouldn't get hot

**If you get caught driving with a gutted converter, your wallet will also be affected

 

when you say "upstream" im assuming the one in front of the cat and there is only one right ??

 

Depends what year & engine. There may be as many as 4 sensors and as few as 2.

 

97 with the 4.3 l vortec

 

Yours has 4 sensors. B1S1 & B2S1 are the upstream sensors that you can remove to test for restriction.