What do you guys think? I just installed a turbo in a friends car, it has thrown catylist efficiency codes once in awhile in the past due to high flow cat on a obd2 setup. This guy had to reweld up my exhaust to fit the down pipe, he cut and made a flange and welded right next to the o2 sensor without dissconnecting it. I now have a o2 sensor code throwing instead of a catylist code. When i drive it in midrange when i hit boost it stops at around 4500 rpm and doesn't want to rev higher, now the gas mileage went through the toilet, and it idles like ****, at a stoplight it bogs at around 400-500 then intermittenly jumps up to 1000 and smooths out for a few seconds, then drops back down. does this sound like an o2 to you? it threw the code last night, and wasn't really idleing bad last night, it started to idle shitty today. Just want some input on if this was a problem for you and if the problem dissapeared when you replaced it. thanks.

 

it sounds like an o2 sensor problem

but if that catalyst inefficiency code comes back get an o2 sim to cure the code