Can an exhaust leak cause my car to run rich?

[deputy865]

My car to run rich? I have a leak in the steel mesh part in my down pipe. Between the o2 sensors. Its a pretty bad leak. Could this cause my car to run rich? Are the sensors getting tricked because of the leak? I replaced both sensors and i have did everything on my CEL pull list but im still running rich. I planned on getting a downpipe anyway to complete my exhaust, but do you think that leak might be the reason for my car running rich?

Thanks,

Shane

 

[lee101315]

It would could throw a cat. efficiency code on an OBD2 car... You should fix it, although its most likely not your problem. Check for air leaks between the air meter and the cylinder head and report back

 

[No_Skillz]

As long as your front O2 gets a good reading from your exhaust, it's fine. The rear O2 only monitors your cat and has no effect on your tune. Your problem lies elsewhere.

How do you know you are running rich? Do you have a wideband? If not, those lame narrowband gauges that connect to your stock O2 sensor are not to be relied upon.