P0171 AND P0174

2005 Pontiac GTO

Tiny

docdiggy

April, 9, 2009 AT 6:56 PM

Computer problem
2005 Pontiac GTO V8 Two Wheel Drive Manual 38000 miles

Since I bought this car back in August I have been getting a MIL and these are the codes. The light will come on and go off every few days to every few weeks. A friend of mine did a smoke test to check for vacuum leaks and found two. He fixed them and no luck. I have also cleaned the MAF and no luck there either.
Recently I had a rough idle and with a scan tool I found out the drivers side o2 sensor was acting up. I changed it and the idle went back to normal and I thought I cleared up the codes, but they came back a week later. Where else can I look to fix this problem? Also, can I be causing damage while this is going unfixed? If this helps, I believe the light only comes on during idle. It is always bank 1 & 2. Thanks in advance.
Keith Anyon

FOUND 129 RELATED QUESTIONS

5 Answers

Tiny

rasmataz

April, 9, 2009 AT 6:58 PM

2005 Pontiac GTO P0171 and P0174

A lean fuel condition can be caused by: * Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (Use a fuel pressure gauge to check fuel pressure at idle)

* Dirty fuel injectors. (Try cleaning the injectors)

* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)

* Leaky EGR valve. (Check operation of EGR valve)

* Leaky PCV Valve or hose. (Check valve and hose connections)

* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)

Tiny

docdiggy

April, 9, 2009 AT 7:09 PM

How can you test for low fuel pressure when you never know when the code is going to come or go? Dosen't that mean whatever the problem is, it is not consistent? The light will come and go even if I don't reset it.

Tiny

rasmataz

April, 9, 2009 AT 7:18 PM

I've given you something to work with that will caused the P0171/P0174 you need to follow up on my earlier suggestions then comeback with some results so that I can continue to assist-

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Tiny

docdiggy

April, 9, 2009 AT 7:40 PM

Is it possible to cause any engine damage by driving until I can try to work with some of the causes that you mentioned? I know lean is not a good thing.

Tiny

rasmataz

April, 9, 2009 AT 7:58 PM

You'll burn more fuel due to the computer compensating for the lean condition could also ruin the catatlytic converter.

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