2006 X5 P0171 P0174 lean codes from hell. HELP!

Maverick88 · 03-08-2023, 10:51 AM

I have a 2006 X5 3.0 that I recently acquired and I have an SES light and two codes: P0171 and P0174 that I cannot resolve. The codes are for "system too lean bank1 and bank2." I have read/watched every forum, video, anything/everything online about these two codes and I am completely stumped at this point. Looking for any help/ideas as I am ready to throw in the towel on this one.

List of parts/troubleshooting I have done:

1.) Performed smoke test - no leaks.
2.) Replaced entire CCV system and all plastic hoses
3.) Replaced intake manifold gasket
4.) Replaced Spark plugs
5.) Replaced intake boot
6.) New gas cap, new engine oil cap.
7.) Replaced fuel filter
8.) Replaced fuel pump assembly.
9.) Replaced DISA valve O-ring
10.) Replaced Pre-cat O2 sensors

The only parts I have not replaced, that I have read online could be the culprit are the DISA Valve and the MAF sensor. I tested both to the best of my ability and both appear to be functioning normally.

The car idles just fine, but there is a noticeable vibration that can be felt once you shift the car into Drive. So sitting at any stop light/red light, at idle, in Drive, you feel a wicked vibration all through the steering wheel and the rpm drops fairly low (goes down to just above 500 rpm). If you shift it into neutral or park, the vibration almost entirely goes away and the RPM jumps up a bit and the idle feels more "normal". Other than this though the car has no drivability issues (for the most part) if you are driving moderately. However, any type of hard acceleration and you notice some hesitation, sputtering, sometimes cylinders misfiring, and and an obvious loss of power. Flooring the gas pedal results in nearly every cylinder misfiring and the car going into limp mode. (only did this once to show a friend how bad the issue can get).

I have an appointment at an INDY in 2 weeks that I am dreading as they are very expensive and do not always resolve issues successfully. Hoping to find some help here from anyone that has some insight into these particular lean codes with this engine.

Thank you in advance to anyone taking the time to read this and respond.

03-08-2023, 10:51 AM	#1
Maverick88 Registered 0 Rep 1 Posts Drives: 2006 BMW X5 3.0 Join Date: Mar 2023 Location: Massachusetts iTrader: (0)	2006 X5 P0171 P0174 lean codes from hell. HELP! I have a 2006 X5 3.0 that I recently acquired and I have an SES light and two codes: P0171 and P0174 that I cannot resolve. The codes are for "system too lean bank1 and bank2." I have read/watched every forum, video, anything/everything online about these two codes and I am completely stumped at this point. Looking for any help/ideas as I am ready to throw in the towel on this one. List of parts/troubleshooting I have done: 1.) Performed smoke test - no leaks. 2.) Replaced entire CCV system and all plastic hoses 3.) Replaced intake manifold gasket 4.) Replaced Spark plugs 5.) Replaced intake boot 6.) New gas cap, new engine oil cap. 7.) Replaced fuel filter 8.) Replaced fuel pump assembly. 9.) Replaced DISA valve O-ring 10.) Replaced Pre-cat O2 sensors The only parts I have not replaced, that I have read online could be the culprit are the DISA Valve and the MAF sensor. I tested both to the best of my ability and both appear to be functioning normally. The car idles just fine, but there is a noticeable vibration that can be felt once you shift the car into Drive. So sitting at any stop light/red light, at idle, in Drive, you feel a wicked vibration all through the steering wheel and the rpm drops fairly low (goes down to just above 500 rpm). If you shift it into neutral or park, the vibration almost entirely goes away and the RPM jumps up a bit and the idle feels more "normal". Other than this though the car has no drivability issues (for the most part) if you are driving moderately. However, any type of hard acceleration and you notice some hesitation, sputtering, sometimes cylinders misfiring, and and an obvious loss of power. Flooring the gas pedal results in nearly every cylinder misfiring and the car going into limp mode. (only did this once to show a friend how bad the issue can get). I have an appointment at an INDY in 2 weeks that I am dreading as they are very expensive and do not always resolve issues successfully. Hoping to find some help here from anyone that has some insight into these particular lean codes with this engine. Thank you in advance to anyone taking the time to read this and respond.
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