rocket22

I have looked up the codes here, is it most likely replacement of the O2 Sensors or wiring? Unusual for both to fail. Car passed back in 2010 (not under my ownership).
How many 02 sensors are on this exhaust?

CalBoy101

Bad news first, there are 4 O2 sensors, good news, if you aren't in a hurry rockauto.com has pretty good prices on the ones that they claim are the OEM ones (NTK).

Changing the back ones is easy but the front ones are a pain, unless you have dinky hands you might need to drop the front exhaust connection down to get to the connectors. Fortunately (and unlike some GM ones) the connector is easy to release, you can get a finger tip on the latch to lift it up and then pull on the wire to pull out the connector but its tight up in there with the exhaust on.

I was changing my exhaust anyway when I replaced my sensors and I don't think my hands would have fit up there with the pipes on, even with the pipes off you have to be good with your finger tips.

petrock

http://www.obd-codes.com/p0171 — System Too Lean (Bank 1)
http://www.obd-codes.com/p0174 — System Too Lean (Bank 2)

I seriously doubt the problem is your O2 sensors. O2 sensors usually don’t fail in a way that fakes the computer into thinking there is a rich/lean condition. They usually fail by their internal heater circuit failing, which is a different code all together.

I think you really do have a lean condition going on, which could be any number of things. Like a vacuum leak, exhaust leak or dirty/bad MAF sensor. Although, since the codes are for a lean condition on both banks it is unlikely to be an exhaust leak because an exhaust leak on one side would not effect the other side. The MAF is sensing how much air is entering the motor, and the computer knows how much fuel it is pumping into the motor and the front O2 sensors are sensing how much air is coming out in proportion to fuel. The O2 sensor is reading more air then it expects in the exhaust given the amount of air that is entering the motor.

I’d start by cleaning the MAF with some MAF cleaner. If that doesn’t help start looking for vacuum leaks between the MAF and pistons and exhaust leaks between the exhaust manifold gasket & the front O2 sensors.

rocket22

I am leaning your way PetRock. I can understand one 02 failure in a short period of time, but I am thinking I have a lean condition somewhere and will start with cleaning the MAF sensor this weekend. Plus my gas mileage stinks. I am also planning on full tune up, EGR valve replacement, and check exhaust for leaks and connections.

Thanks again for the reply!!!

petrock

A lean condition would explain your crappy milage. The computer is dumping more fuel into the motor to try to correct the lean condition, but its run out of adjustment. So it throws the lean codes.

Good luck...