Whats up everyone im having a few problems with my car. One is for the past few weeks my car has been hesitating & stumbling when i step on the gas in either 1,2,3rd gear. I took it to my mechanic last week couldn't find anything wrong..... whatever. I got a new catback (gmmg) when it got installed it sounded great. No rasp or popping sounds.Few weeks later exhaust is makeing popping sounds. it doesn't even sound like the same car sometimes. Last night my SES light came on and the car was stumbling very bad. Took the car to my mechanic today and they said the o2 sensors went bad. Is this what is causing my stumbling and popping sounds from the exhaust? I notice my gas mileage has gone down a bit can the sensors affect this also? I haven't picked my car up yet so i haven't been able to test it out. Whats the purpose of o2 sensors? I want to learn more about them and how they affect our cars.

Another problem i have is when i got my gmmg installed the guy who worked on my car pointed out that my Passenger side headers was "banging against the k-member . I notice when i start my car up when its been cold i can hear like the headers vibrating against it on the passenger side. How big of a problem is this? After the car has warmed up i don't hear the vibration anymore. Can this be fixed?

Also changed plugs and wires In november (this year). Opti is less then a year old. Car has 67,000 miles

mike

 

....notch the k-member with a torch....

 

Had to have 1/2 " cut out of my K member to clear the headers. Then welded on a "patch" to cover the hole. That's why so much was cut out.

 

Will cutting or torching the k-member do any harm to my car? Whats the k-member for? What about my other question about the o2 sensors?

Thanks

 

My headers used to hit my k-member everytime I came to a stop, made a very loud banging sound. Put in new motor mounts (I did polyurathane mounts) and the problem was solved. I have twice as many miles as you and my motor mounts were sagging badly so new ones fixed my problem.