P0171

[bop]

Hi, as stated I have been getting aP0171 code.
With my elm dongle and smart phone app the fuel trim goes to +25% on bak one bank 2 normal+/- 2.5 %.
The bank 1 position 1 (upstream) o2 sensor is locked at.1 -.2 volts, bank 2 cycles between .1 -.8 volts as it should. Both down stream o2 sensors are steady ar .7 volts which is as expected.
There is no air leak I can find al the bank one components are a dog to get to. I am thinking the 02 sensor is shot, 200000 KM. The only other thing I was thinking is a clogged injector. What do you people think?
Cheers Brian

[VroomVroom]

yes its the O2 sensor , if the values dont change regularly its buggered.

a bad injector will cause funny readings on both sensors of the affected bank . plus will bring up a different code

[vnboost]

Do a few snap throttles whilst looking at the bank one O2 readings or introduce some propane to the intake and watch the values, if they dont move chances are O2 is buggered.

[bop]

Thanks for both replies, the ist 02 sensor stay pinned at .1-2 V with a blip on the throttle.
Two new sensors on order.

[bop]

Soooo, 02 sensors arrived but not installed yet. Fuel trims have gone back to normal %. 02 volts are fluctuating between.1-.7 as is normal. WTF is going on, is that normal for an 02 sensor on its way out?
Brian

[lsemmens]

Yes. I had all sorts of problems just recently on my Jack. Reports told me the MAP sensor was sufft. (I was suspicious, so got one out of a wreck) Made no difference. Intermittent running foul then suddenly came good. Replaced O2 sensor and have not had a problem since.