I have had some serious 02 sensor issues my car will barely run once it gets into closed loop mode. It will run perfect with my other computer that I have programmed to stay in open loop. Anyway I have gone through 2 sets of 02 sensors with no fix. I just got another code saying sensor circuit voltage low. Anyway I found a leak in my long tubes right where all the primaries come together. This is about a half a foot before my 02 sensor. Can such a leak cause 02 sensors to get some jacked readings? The leak doesnt look too bad but I saw some black sut in that area. Thanks for any help.
JT

 

Yes, it will give bad readings to the O2's. They will think that the car is running lean and dump alot of gas to make it run richer.

 

what he said. O2s adjust the way the car mixes air/fuel, etc. to fix a condition if it exists. this could be your problem.

 

these are the codes I get while running in normal closed loop mode with my long tubes....
P0151 Bnk 2 Sensor 1 Sensor Circuit low volts
P0133 Bnk 1 Sensor 1 slow response
P1153 Bnk 2 control shifted lean
P1133 Insufficient switching Bnk1sens1

Hope this helps you guys out some.

The leak is on the passenger side header as I said im not sure how much of a leak it is im just trying to see if the codes I received sound like thats what it is. I have tried a couple different pairs of new 02 sensors so its not them.

 

I had an exhaust leak in my SLP headers. The leak was at the collector, just above the O2 sensor. When I finally got it fixed (took three tries), it was incredible how much of a difference it made.

BRAD