Code P1171

[snowtrooper1966]

The Dragon is giving code:
P1171
and my code reader is displaying:
"Unidentified Code"
Thanks in advance for any info...
Best,

[Ldub]

P1171
Fuel System Lean During Acceleration

[Jolly Roger VX'er]

Clear the code and see if it comes back...also see if it happens while going up a hill.

Mine kicked this code whenever you started putting the spurrs to her while going up a hill...after changing things out (fuel filter, intake gaskets, bad injector O-rings, a cracked fuel injector...) it wound up being my MAF sensor. Try cleaning that first.

I never did get a MAF sensor code though..which is why it took me a while to figure out and fix the problem.

[snowtrooper1966]

Thanks, gentelmen!
No symtoms at all.
I changed the fuel filter last summer, as well as trated the fuel system with seafoam.
I am also getting codes:
P0137 02 sensor circuit low voltage (bank 1 Sensor 2)
&
P0157 02 sensor circuit low voltage (bank 2 sensor 2)
I am guessing I need to replace the post cat 02 sensors?

I have cleared the codes, and they come back pretty quick.
I will clean the MAF and see what happens with the P1171 code.
Best,

[Jolly Roger VX'er]

Thanks, gentelmen!
No symtoms at all.
I changed the fuel filter last summer, as well as trated the fuel system with seafoam.
I am also getting codes:
P0137 02 sensor circuit low voltage (bank 1 Sensor 2)
&
P0157 02 sensor circuit low voltage (bank 2 sensor 2)
I am guessing I need to replace the post cat 02 sensors?

I have cleared the codes, and they come back pretty quick.
I will clean the MAF and see what happens with the P1171 code.
Best,

I got one of these oxygen sensor codes too when I had the previously mentioned problem. Autozone wanted to sell me an oxygen sensor but I tried cleaning the MAF first. When that didn't help I opted to replace it (nobody tests them.) That wound up clearing up "both" of my trouble codes of "Lean under acceleration" and "P0157".

[snowtrooper1966]

Oh, and many thanks to Tone for the PDF! Invaluable info for all!

Jolly Roger VX'er, so based on your experience, changing the 02 sensor cleared both codes?

Am I correct in thinking the 2nd sensor in both banks is the post cat?

Best,

[Tone]

P1171 Fuel Air Metering / Fuel System Lean During Acceleration
- could be dirty maf, dirty intake air temp sensor, clogged fuel filter and/or clogged EGR. Any symptoms? Search .info for where these are and how to address the issues. And actually a search for P1171 brought up info on this very board from 2004...

BTW, Anything above P1000 will be Manufacturer specific and NOT in a general list of codes. See attached PDF

[Vendetta]

Forgive my waking this tired 'ol thread, but I'm having the EXACT same codes thrown at the moment.

P1171 - Fuel System Lean During Acceleration
P0157 - O2 Circuit Low Voltage (Bank 2 Sensor 2)
P0137 - O2 Circuit Low Voltage (Bank 1 Sensor 2)

My wrench swears up and down that he already replaced all the O2 sensors with brand new ones. He's at a loss. Therefore I am at a loss.

Snowtrooper, can you put please a ribbon on this one and tell us if and how you solved this set of codes?

Thanks,
-V

[Ldub]

Forgive my waking this tired 'ol thread, but I'm having the EXACT same codes thrown at the moment.

P1171 - Fuel System Lean During Acceleration
P0157 - O2 Circuit Low Voltage (Bank 2 Sensor 2)
P0137 - O2 Circuit Low Voltage (Bank 1 Sensor 2)

My wrench swears up and down that he already replaced all the O2 sensors with brand new ones. He's at a loss. Therefore I am at a loss.

Snowtrooper, can you put please a ribbon on this one and tell us if and how you solved this set of codes?

Thanks,
-V

I'm fairly certain that those codes are indicative of unmetered air getting into the intake system, somewhere downstream of the MAF sensor.
Could be vacuum leak (hose or otherwise)
OR, vacuum leak (intake manifold gaskets)

Look HERE

[Child's Play]

Forgive my waking this tired 'ol thread, but I'm having the EXACT same codes thrown at the moment.

P1171 - Fuel System Lean During Acceleration
P0157 - O2 Circuit Low Voltage (Bank 2 Sensor 2)
P0137 - O2 Circuit Low Voltage (Bank 1 Sensor 2)

My wrench swears up and down that he already replaced all the O2 sensors with brand new ones. He's at a loss. Therefore I am at a loss.

Snowtrooper, can you put please a ribbon on this one and tell us if and how you solved this set of codes?

Thanks,
-V

V,
Just got the same code today as well.... Must be the nice weather. Anyway, on my last VX I had this code as well and it was the intake gaskets (very common). I'm gonna take mine in shortly to have it diagnosed, but I'm pretty positive this is what it is as I hear a slight vacuum sound coming from the engine bay.

What is the mileage on your VX? Mines @ 72K

CP

[Vendetta]

Thing is, my wrench cleared the codes this morning prior to my 100-mile trek to the yard and back, and they haven't come back on.

Granted, I was driving on eggshells going for maximum MPG, but still... I would think they'd come on if it were something like a gasket leak. I don't know, so here I am.

-V

[Ldub]

Thing is, my wrench cleared the codes this morning prior to my 100-mile trek to the yard and back, and they haven't come back on.

Granted, I was driving on eggshells going for maximum MPG, but still... I would think they'd come on if it were something like a gasket leak. I don't know, so here I am.

-V

Yep...

Same experience, as long as I'm a "good boy" with regard to the skinny pedal...nothing.

But when I drive "normally", I would get the same codes. Start with a good maf cleaning...

[Cobrajet]

Thing is, my wrench cleared the codes this morning prior to my 100-mile trek to the yard and back, and they haven't come back on.

Granted, I was driving on eggshells going for maximum MPG, but still... I would think they'd come on if it were something like a gasket leak. I don't know, so here I am.

-V

Yep...

Same experience, as long as I'm a "good boy" with regard to the skinny pedal...nothing.

But when I drive "normally", I would get the same codes. Start with a good maf cleaning...

I had that P1171 code years ago, and it would go away for days, only to return when I took one particular uphill stretch from a right turn. Because it was a 50 mph zone following a blind curve I always had the pedal to the metal. I had the dealership clean the MAF on my next service call, and I replace the K&N filter with a stock one, and have not had another code since.

[Vendetta]

Hey CP,

I'm at 90K now. And the CEL is doin' its thing. I've cleared it a few times, but like Dub says, when I get on it a bit, the light comes right back on and stays on 'til it's cleared.

I'll have my guy look at the gasket leaks - eventually.
-V

[89Vette]

Hey CP,

I'm at 90K now. And the CEL is doin' its thing. I've cleared it a few times, but like Dub says, when I get on it a bit, the light comes right back on and stays on 'til it's cleared.

I'll have my guy look at the gasket leaks - eventually.
-V

If you've got a propane torch, just turn it on and run it around the perimeter of your intake. If the engine speeds up, you've got a leak. Some people use starter fluid, but it can be a fire hazard if you've got spark exposure.