I put on a MXP testpipe a few months back. Originally, I had the rear O2 sensor connected directly to the MXP testpipe. Which has a rear O2 fix built in, however after about 500 miles I get a p0172 (O2 sensor rich code). I installed the Touge Factory 90 degree elbow and now the car is throwing a p0139 (rear O2 lean/ heated O2 sensor low circuit), means its out of the exhaust flow too much.) Did anyone else experience this issue at all?

I might try to get regular antifowlers and drill them out and see if extending the O2 will fix it.

Any input is appreciated.

~Kris

Note: The MXP O2 fix, consists of a extended O2 bung and some wire mesh inside the extended chamber to prevent some of the gases to flow in.

 

I tried the antifouler idea and it didn't work...... I have since removed the sensor all together but left it tied up under the car and plugged in... I was custom tuned and about 25ish miles afterwards got an SES light immediately pulled the code it was P0140 which is rear o2 sensor inactivity... Talked to my tuner and he said he had a fix for it so I went back he flashed it in... This worked for about 30ish miles or so and got the light again soooo... we are battling this as well!....