Ever since I installed my long tube headers my car has run like ****. I will try and make this short as possible but here goes:
I originally was running mac shorty headers, no cats, and pcmforless OBD2 tuning. I then installed new hooker longtubes with mufflex y-pipe. After this my car seemed to run ok but still didnt seem powerful. I went to the track and found I ran .4 tenths and 3mph slower than my previous best with shorties. Ok something isnt right. On the way home from the track my SES light came on it was code P1133 (H02S Insufficient switching Sensor 1/bank 1 Fuel control shifted lean). After reading this code I immediately thought it was a bad 02 sensor which seemed reasonable as I had some cheap ones in there. I bought 2 new GM 02 sensors and this did nothing. I still received the same code P1133. Now I thought just maybe I happened to get a bad sensor from GM so I swapped sides and then SES came on again. I get the car scanned and now im getting 3 codes: P0133 (Bank 1/ Sensor 1 02 slow response), P1153 (Bank 2 fuel control shifted lean), and then P1133 again which is same code as previously mentioned above. Guy at the shop said its still possible that its a bad 02 and by switching sides it triggered other codes P1153 being the frist one which is bank 2 which was originally the sensor which triggered the original code. I used a pair of my friends old 02 extension wires which could be bad but most likely not. No 02 wires are burnt or touching anything hot. I also replaced the plugs, new wires, tried a different opti and coil, new fuel filter, and just installed a brand new OBD1 conversion PCM thinking that maybe the car was leaned out for my shorties and now with long tubes was running to lean so the computer ran in "safe mode" and richened the mixture a lot. So after installing the OBD1 conversion PCM I was excited thinking everything would be fixed, wrong. The car seems to run pretty smooth and strong at WOT, however during normal acceleration it stutters (you can literally feel the car loose power, then add it again it actually jolts you back and forth during acceleration). Since 02 sensors are not read at WOT this is why im still leaning towards something wrong with one of my new 02's or the old 02 extensions. Well, from hearing my situation, and the codes im getting can anyone give me some more info this car is driving me nuts.
Thanks a lot,
JT

 

With a slow/no-response code make sure there is no leaks near O2's.

+ are you sure these new L/T's are not causing an igition wire issue with it poppin & surgin?

That sure sounds like ignition to me.

Worked on lots of LT1 cars, same prob, same mods.

 

Just got my car scanned due to similar issues. It was not the o2 sensors in mine. All my codes are due to to lean of a fuel mixture. Looks like I am going to need a tune.