Anyone ever get a P171 code? If so what did you do to fix it?

I have one that is resettable but comes back from time to time, no relation to driving conditions etc. 1998 4.6 97K miles.

 

Could be a vacuum leak.Check all of your pcv lines,esp. the rubber boot under the throttle body.Also,could be a dirty MAF sensor.Maybe an O2 sensor.

 

I checked for vaccum leaks already, have not checked the MAP sensor. Will check that. Thanks

 

Try changing the fuel filter. It worked for me.

 

PO171 is the "Lean on Bank 1" code. If you didn't get anyother code then this means that whatever the problem is it's only effecting the right bank (I think bank 1 is right side cylinders). Vacuum leaks would generally be causing lean on both banks - 2 codes.
I suggest swapping the o2 sensors around and see if the problem swaps sides.

 

Bank one is the passenger side. Did you clean the MAF?

 

Not yet but plan on it this weekend. Thanks for the info.

 

Cleaned the MAF (did not look dirty but cleaned it anyway). Reset the computer and seems to run better. Time will tell if it fixed the problem. Thanks for the help.

 

just for info i had the p171 code and had a vacum leak , the rubber elbow on the PCV tube. not always will the codes be tripped for both left and right bank lean code with a vacum leak, that same vac leak would trip serval differant codes eachtime i cleared them but the p171 stayed

 

Thanks, I checked all the hoses and they looked good.

 

did you pull the rubber elbow off and look for cracks? you won't see them unless you do .the rubber gets soft and collaspes..or have the engine running and feel for the leaks

 

I have a 98 5.4L with 94K miles. My "Check Engine" came on about 2wks ago with a p171 code. Turns out that I have a vacuum leak on a hose behind the "Air Intake Control Valve". I found it by using a 2' section of garden hose with one end held to my ear as I moved the other end around the various vacuum hoses (engine running). I'm waiting for the engine to cool before I reach back there to change out the short section of vacuum hose. I'm pretty sure that's what my problem is.

 

Thanks for the info, will check this as well. Since I cleaned the mass airflow sensor I have not had any problems. But, that is the way it has been acting. Runs fine for a while then out of the blue get the check engine light with the P171 code every time.

 

a good replacement for the elbow is the rubber boot from a coil wire {old style} with the 90 degree elbow, the rubber is twice as thick. cost about 2 bucks verse's $28-35.00

 

after 3 different mechanics did about $1200 in repairs, and hours and hours of headaches on my part, I found a spark plug had cracked and caused my lean condition. cost was $5.95