99gtp p0171

I have a 1999 Gtp (3.8 S/C) with 115k miles that is giving off the P0171 code. Other than my gas mileage being horrible the last few months, my car is running the same it always has. The code set the SES light two nights ago while I was letting the car warm up on my way home from work. It has been between 0-20 degrees here for about a week. Is it possible the cold weather along with a faulty sensor is the issue?

I'd rather not pay to replace a sensor that is working correctly, however I'm not having any driveablity issues or other codes to lead me in another direction. Any help or ideas on the issue would be greatly appreciated.

-Justin

It's probaby bad plastic, rubber, or gasket causing unmetered air leaks.
The unmetered air leaks will cause your car to run lean, and throw codes.

Suspect -
Air duct work going from the air box to the throttle body.
Leaky PCV system
Leaky EGR system
Bad Intake gasket

Do a google ''Youtube Auto smoke test'' watch the vaccum leak video

Well, I went to go take a look at the car this morning and on the first start the SES light went out. I drove the car around a bit today and it hasn't come back on. The temps. here have gone up a little from the last few days so maybe it was false code with the cold weather.

Either way, I'm betting on a faulty O2 sensor, so I'll be ordering a new one from ZZP. Then we'll see if the code comes back with the new one.