Your car is adding an insane amount of fuel to the engine to keep it running. This could be due to many factors: A vacuum leak, a bad MAF sensor, a bad air-fuel ratio sensor, a bad oxygen sensor, bad fuel pump, bad fuel pressure regulator, bad fuel injectors, etc.

What is your MAF sensor reading (in grams per second) at idle?

 

I unplugged my MAF sensor while engine was running and it stalled so I assume it’s doing it’s job.

 

Every time you start your car, the car's computer uses pre-determined values to keep the engine going. It's only after the car enters into "closed-loop" that it starts using info directly from the various sensors to keep the engine going. Removing or unplugging the MAF sensor should not stop your engine from running, it just might run a lot worse or even better. There is a chance your MAF sensor could be bad.

If you are able to post your MAF values at idle, it would allow for a better diagnosis.

 

It's most likely your 02 sensor. That's what I'd change if I couldn't find any exhaust leaks.

 

That is a possibility, if any are bad, then most likely it's the Air-Fuel ratio sensor (aka Bank1Sensor1).

 

I don't know what year or how many miles are on your car, and I'm guessing it's a 4 cylinder because there's only 1 bank.

Isn't there a readout on the obdii that checks your sensors? I'd change the 02, reset the code and then watch the fuel trims after you installed the new O2.

 

Since the fuel trims are high. can it also be a vacuum leak?

 

Yes. It could be a dozen different things.

 

I'd look for vacuum leaks first. If no luck I'd change your air filter if it's been a while, then reset the code. Lastly I'd change the 02 sensor. Your maf is working as it should it's your 02 sensor. There easy to put on. It will be the one in front under the heat shield.

 

I have fixed that code with a bottle of techron and nothing else, didn't even reset the ECU, might be the first thing to try if you haven't already. Poor injector spray patterns can be cleared up with injector cleaner and techron is what fixed my car on more than one try and only that cleaner, nothing else.
A few bucks at walmart.

 

2cold vacuum leak can be verified if you will monitor fuel trims while raising RPM.
Post the fuel trims you have at 3000RPM.

 

here is the 3000rpm

 

Ok, since stft is down about 27% suspect vacuum leak.
If you keep the idle up high for min or two LT probably would come down also.
A shop should be able to locate the fault quickly.
DIY- check appropriate after MAF intake/vacuum line connections by spritzing water around suspect areas looking/listening for hissing/bubbling that indicate a vacuum leak.
If no external leak then check braked booster vacuum line/ purge solenoid vacuum line /PCV for leaks.

Good luck and let us know how it goes.

 

 

Update no vacuums leaks found. I used water and carb cleaner but nothing.

 

May have to have a shop do an intake smoke test and test for possible brake/purge/pcv vacuum leaks.
Regrading testing for vacuum leaks need to remove engine cover and locate all vacuum hoses connecting to the intake manifold.

 

Any symptoms besides the code and high fuel trims?

 

The MAF is reading low should be around .33 lb/m at idle.
Low MAF reading will add to positive fuel trims.
Try cleaning see if helps any.
Question: did the high positive fuel trims come on recently?
Any work done recently that may correspond to the high trims.

 

The check engine p0171 has been on for a couple months but I just now checked with a better reader.

 

Ok, best i have now is to clean MAf sensor see if positive trims come down at idle if not then probably best to get some help from a shop.