2000 V6 P0171 & P0174

I have a 2000 mustang with the 3.8L V6 and recently the CE light came on. Stopped at Autozone and it's throwing two codes P0171 & P0174 (System too lean Bank 1 and 2 respectively).

I replaced the fuel filter and air filter, checked the PCV valve (still getting good vaccum, so didn't replace) and cleared the codes by disconnecting the battery. Also put in some fuel injector cleaner and after about 15-18 miles, the light comes back on with the same codes. Any ideas as to other things to try? Also, is it possible that it may just take a while of driving for it go off? When I replaced the fuel filter, the gas coming out was actually pretty nasty, almost rust colored...

Thanks in advance for any help you folks might offer!

Almost a rust colored gas from the fuel filter? Let your gas tank run almost empty and go put some 93 in it. Also get some octane booster. Try to find out how that rust looking stuff is getting in there. I'll see if I can find anything that might be more helpful.

Yes, that was from the inlet side of the fuel filter, which made me think that would be part of the lean condition, due to blockage. What little fuel I got out of the outlet side looked pretty normal. I filled up with 93 last night after replacing the fuel filter, and as I said I did put fuel injector cleaner in with it. I'll swing by Autozone after work and pick up some octane booster as well to see if that helps.

The only thing I've been able to find so far about these error codes are in relation to the Windstar. In fact, there's a TSB regarding some bolts under the valve covers and grommets/seals in the manifold that are failing, causing oil to get sucked up into the intake some how and causing the sensors to read lean, when in fact it's not lean. I'm not so sure that it's the same engine though, although the pics are close and it is a 3.8L V6 as well.

Thanks for the suggestions, I'll post back if there's any change or I find any more information.

O2 Sensors are probally shot by now, if your car ran lean, it will cook the O2 Sensors up top. Also, if you have rust in your fuel tank, you might want to flush it out, take the fuel pump out and take a closer look in the tank.

if you have a maf sensor on this car take it out and clean it with some brake cleaner and let air dry.

if you have a maf sensor on this car take it out and clean it with some brake cleaner and let air dry.


NO clean it with electrical contact cleaner in which you can get from Radio Shack. Don't use brake cleaner, unless you want to replace the MAS sensor like I had to.........

And ALL 99+ mustangs have a MAF sensor.

Almost Always The Mass Air Flow Sensor Lead Wire Is Covered In Debree To Cause This Issue. You Can Clean It With B-12 Or Brake Clean And A Soft Brissle Brush . Rust Colored Fuel Out Of A Fuel Filter Is Normal When Has Not Been Changed At Normal Service Milage.

Whats up??? Im a new member, got a few questions about my car and friends car help!

Here it is... i drive a Mustang V6 automatic, i know, i know
It is my first car, so im pretty proud of it, so lay off
My friend just recently bought one of those darn dodge neon sxt's (i think they're called) he cant drive stick, so i kno its an automatic. I want to race him and prove he should have stayed with ford, but honestly have no clue who is faster... Any help would be appreciated

Hey, how u doing im new at this wondering if u could help be with this.... i drive a V6 auto stang, dont laugh, its my first car and i pay for it by myself! Friend just got a neon how fast are they???

The SRT-4 Dodge Neon's are about as fast as a STOCK 99~04 GT mustang. There is a pack of them I mess with all the time, they are always trying to run me.
There is one that did some turbo upgrades, last time we ran head to head at sac raceway, he pulled a 13.47@104 to my 13.39@107... in other words... they definately have the potentual.


BTW, I'm at the point where I need major mods (Blower, NO2, or Stroker) to go any faster (without stripping the car), I already pretty much did all the nickel & dime upgrades.