Ok, next problem. Check engine light came back on. Had Autozone read the code. Code says running lean bank 1. Offers possible problems. Only thing I haven't changed is the o2 sensor. Think that'* the problem?

very rarely is it the o2 when you have lean codes.they have there own codes

you check fuel pressure now with the new battery?

Whoa,, let'* keep one issue per thread please. This is to prevent confusion in the future and long page reads.

JW, It has thrown this code for quite some time now. Any suggestions? Car has 180+++ miles

lean codes are tough. the first thing is verify fuel pressure. then most common is vacuum leaks, there are very many places it could, the 3800 has a common place that is the boot that feeds the evap and fpr. the boot gets heat soaked from the engine cover and looks dry rotted if so replace it and the lines to the fpr/purge solenoid.

Code says running lean bank 1

Technically, there is no such thing, since you only have one O2 sensor for fuel management...that O2 sensor is affected by both banks.....

could be any number of things....I doubt fuel pressure if it is running ok....like the guys said, could be a vac leak.....could even be an exhaust leak at the doughnut of the ex manifold......could even be a bad MAF(you would need a scan tool to see this, by watching O2 data while disconnecting the MAF).....could be a bad O2 sensor(could also be contaminated, coolant or carbon), but you should create a lean/rich condition and watch O2 sensor, to see if it responds....

Well, thanks for the info. Sounds more complicated than I can do. Have replaced MAF sensor, and apparently it was not the problem.

Actually, the PCM can differentiate between both banks via 1 sensor. It adjusts fueling between the banks and watches the O2 for any changes. This is how it knows which bank it is. Same thing with knock sensors, on a V8, a computer using 1 knock sensor can pinpoint which cylinder is misfiring.

In his case, the rear bank injectors are getting most of the fuel(due to the **** poor design of the fuel rail) and the front bank(or bank 1) is getting the least amount of fuel. So in his case, a weak fuel pump/or low voltage at the pump can cause him to have a lean bank condition.

Actually, the PCM can differentiate between both banks via 1 sensor. It adjusts fueling between the banks and watches the O2 for any changes. This is how it knows which bank it is. Same thing with knock sensors, on a V8, a computer using 1 knock sensor can pinpoint which cylinder is misfiring.

You may be right Mike, but I don't think the PCM is set up to do that......looking through a manual, I see P0171 ......I do not see P0174 for this vehicle....I think you need O2Bank2sensor1 for that code, and to be able to differentiate which bank is running lean........

In his case, the rear bank injectors are getting most of the fuel(due to the **** poor design of the fuel rail) and the front bank(or bank 1) is getting the least amount of fuel. So in his case, a weak fuel pump/or low voltage at the pump can cause him to have a lean bank condition.

I wonder about that.....has anyone ever installed a fuel gauge just before the rail and also at the schraeder, to see how much of a difference in fuel pressure, there actually is? A fully functioning fuel pump doesn't set a code for a lean bank, so if you have low voltage or weak fuel pump, the drop in pressure will be proportional to both sides, and won't register as one bank being leaner than the other....of, course I could be wrong......