Thread: P0171 Front Bank Lean

Alright, running out of hope with this code.

It's a 2000 GT 3.8 and been getting this code for a couple months now. It is for the most part a steady light however it has randomly shut off for just a very split moment just a couple times over the months. Nothing seems wrong with the vehicle other then bad gas mileage.

Idle is fine (around 850) Acceleration is fine. Everything seems just fine. No unexpected noises, just a SES light and bad mileage.

Recently had the lower intake gasket replaced due to having an oil leak up at the front of the engine but appears that I may be burning through oil (though not enough to see smoke, just not seeing a leak and have to drop a quart in at least once before regular oil change)
Since the SES light has come on, I have replaced:
Upstream O2 sensor
MAF
Intake manifold
Various vacuum lines
Along with other various typical spring time tune up things (clean air filter, changed oil)

Taken it to a couple different mechanics and basically been charged $100+ to have them reset the light and tell me to piss off.. not in the best mood with "mechanics" right now. Last one did tell me that the injectors appear to be all working fine but I'm not sure I believe him since he also told me they took it for "an extensive test drive to see if the codes would return" and apparently an "extensive test drive" only covers a tad bit over 1/10th of a mile.

I have attempted the carb cleaner over the entire engine to see if there was a change in rpms to find a vacuum leak intake side but came up with nothing.

I'm in hopes that someone may have any other ideas on what to look at to get fixed to solve this code. Because of it only being the front bank code and having no noticeable loss in power, I am not thinking it is fuel injector related and my last guess would be the front exhaust manifold gasket. Is there any good way to check this? or is that something I would be able to hear being a problem?

Thanks for anyone that could give some sort of help with this, I'm getting tired of the SES light being on all the time.

Originally Posted by 00grandprixgtp

what is the fuel trim at and are you on the same tank of gas? sometime bad gas can cause that code

It's not bad gas, it's been a lengthy problem now and I don't have tools to check trim. However, after reading through a bunch of different posts and not even thinking of an EGR issue (figured that would be it's own code) I did nothing more then unplug it and on next start, the SES light was off. I don't get it, It doesn't make sense to me that unplugging the EGR would cause the light to go out on next start. I thought the system basically had to go through a few checks of the system to automatically shut off a SES light.

Oh well, I plugged it back in but the light wasn't on when I restarted this time. Going to try and get the light to come back on and then unplug the EGR again to see if it goes out.

Now, if it does have something to do with the EGR and since I'm not getting a code for it, would it be more likely that it has something to do with the lines that go into it or the EGR itself might be bad?

i have this code now after replacing rear o2 and bending back a bent exhaust.. i bet a cracked a pipe somewhere lol

oh no i had a bank 1 sensor 2 code, replaced that and fixed it.. then the p0171 code came up after my o2 sensor was working again which showed me that i had a broken vacuum hose which was replaced and fixed the p0171.