Anyone help me with this?

[NEVRL8T]

I have a 2002 Chevy 1500 Z71 5.3L Vortec powered pick up. I am getting a lean on right bank. I am thinking O2 sensor but I wonder how I can tell which one. I think it has two in front of the cat and one behind. These things are $70 bucks a pop. Any ideas? TIA.

[Y2Kvert4me]

First, check for any possible induction air leaks between the MAF sensor and throttle body.

If nothing found, the 02 sensor to suspect would be the front one on the right side (bank 2). The aft-cat 02 sensors only monitor for cat efficiency, they do not control fuel trims (which +25% trim sets off the lean codes).

As a freebie test, you could swap the front 02 sensors side-to-side, and see if the problem follows the sensor or remains on the right bank.

:cheers:

[03SlowZ06]

The actual code number would help also.

[Garb55]

The actual code number would help also.

:above:
Not sure your Location but in TX Auto Zone will give you a free scan and will tell you the Code. If you know the Code then you will have a better Idea on how to resolve the issue.

[NEVRL8T]

Sorry fellows, I took it to AutoZone and got a PO171, I should have put that in my first post. I went out this evening to coach my son's basketball team and the SES light went off.

[03SlowZ06]

Bank one sensor one. I would clean the MAF with electrical contact cleaner. CRC is the best IMHO. Make sure there are no vaccum leaks. Clear the code from the history and see if it comes back.

[Crowvet]

Do you by chance have a K&N air filter? Sometimes the filter oil will stick on the MAF sensor wire causing dust bunnys to collect on the sensor hot wire. This can skew your sensor reading and cause a lean condition.