97 z71 exhaust problem

I have a 97 z71 5.7-- took out tranny and the exhaust just past the manifold busted on me-- took it to a muffler shop and they welded it-- the welds did not hold up and to purchase this would be 360 for the 2 catalytics, and 2 pipes leading to manifolds--anyway, my truck seems like it is running off of 6 cylinders and it is missing BAD, very hard to start also!!! The computer states that bank 1 and bank 2 is lean and multiple misfires. Would this be the 02 sensors on the passenger side manifold/exhaust?? Or is there a bigger problem here?? That is where the pipe was busted off flush w/the 3 bolt manifold. I believee that some air is getting in through that pipe telling the o2 sensor that it needs more gas-- Make sense?? I dont know--Any help would help, Iam currently laid off and dont have any cash after getting the tranny done. Now I have no vehicle-- HELP!! please

if the comp. says its running lean then I would think the 02 sen. is not working.If you were getting air in there the 02 would tell it to run richer(more gas) you can test the 02`s with a multi-meter a good shop could do that for you. you did no say but I take it the truck ran ok befor the pipe was welded. If so I have a fealing the smoke and gases from that may have done somthing to it. I have a 94 with 168000 on it with stock 02 sensor.this is not an insult but check the connectors and the wireing would not be the first time it was just a connection prob.

if the comp. says its running lean then I would think the 02 sen. is not working.If you were getting air in there the 02 would tell it to run richer(more gas) you can test the 02`s with a multi-meter a good shop could do that for you. you did no say but I take it the truck ran ok befor the pipe was welded. If so I have a fealing the smoke and gases from that may have done somthing to it. I have a 94 with 168000 on it with stock 02 sensor.this is not an insult but check the connectors and the wireing would not be the first time it was just a connection prob.
The truck ran ok just pretty loud-- It is running lousy-- missing and no kind of take off even when you have the accelerator pressed quite a bit. The truck raced up to 4500 rpms going on to the entrance ramp of the x-way and then the sel came on then it started blinking-- Took it to auto zone and they placed it on a hand held diagnostic and that stated running lean and multiple misfire. I checked all wiring going to the (4) o2 sensors and they are fine with no kind of disconnections or damage to wires. I put new plugs and wires on-- that did not work and I will be putting a new cap and rotor on-- any other suggestions??

why did you pull the trans ? this seems to be where the prob. started. "the sel came on then it started blinking" are you talking about the check engine light? the trans in these trucks will spit out a code if there is somthing going on in there. did auto zone get any other codes or did it just state the prob ? does the truck shift ok or do you notice it now wants shifts at a higher RPM

why did you pull the trans ? this seems to be where the prob. started. "the sel came on then it started blinking" are you talking about the check engine light? the trans in these trucks will spit out a code if there is somthing going on in there. did auto zone get any other codes or did it just state the prob ? does the truck shift ok or do you notice it now wants shifts at a higher RPM
The trans was pulled to be rebuilt since the sun gear shell busted into peices-"sel" sorry meant "ses" service engine soon.-- The codes were bank 1 and bank 2 running lean and multiple misfires-- truck shifts better than what it did b4 rebuild-- I replaced the cap and rotor and it seems like the misfires are gone but I still have the bank 1 and bank 2 issue-- Is that the co2 sensors bank 1 drivers--bank 2 passenger? Or does that refer to the Fuel Injectors or intake?? i.e. drivers side bank 1 --passenger side bank 2?? I dont know Iam just doing some guessing-- THe truck has 183000 on it and this is when all sorts of things can go wrong. Thanks alot riderred for responding!!!!

a quick call to a gmc dealer would answer that but I would think the drivers side would be bank 1 since that is where1-3-5-7 cyl. are and pass. is 2-4-6-8 on my 94 I have only 1 o2 located where the y pipe meets you could pull a few plugs and check them check this site on how to read them http://www.centuryperformance.com/spark2.asp
how is the MPG any big change?