Likely cause of P0171 -Powertrain System too Lean (Bank 1)? | Ford Explorer Forums - Serious Explorations

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Likely cause of P0171 -Powertrain System too Lean (Bank 1)?

SyberTiger

Well-Known Member
Joined
May 18, 2007
Messages
767
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52
City, State
Orlando
Year, Model & Trim Level
2002 Limited 4x4 4.6L
I recently experienced yet another episode of weird/high idle (2000 RPM) which usually occurs for me about every six months. When it happens I always:

(1) Disconnect the battery
(2) Clean the MAF
(3) Clean the intake and throttle butterfly
(4) Clean the IAC

This always solves my idle problem for 6 months. So, recently it happened again. I went through my procedure and sure enough it fix my problem. However, within a day or two I threw a P0171 code. What's the best bet as to what the likely problem is? I have about 148K miles on the Explorer now.

I'm curious to know if P0171 is related to leaks on the crossover ... and for that matter can it relate to the idle issue that keeps repeating?

Background info: My oil filter adapter was leaking about a year ago so I got in there and replace the oil filter adapter gasket. After a few month of that fix I noticed and oil leak on the garage floor and thought that perhaps I didn't properly torque the oil filter adapter and maybe it was leaking again. But, when I took a close look it looked like oil was coming from somewhere else but it wasn't obvious where. After a couple of months I noted a drop or two of coolant on the floor. At that point I figured it's probably the crossover since so many have had a leak issue. Upon closer inspection from the top I could see small amounts of coolant sitting around the spark plug of the number 3 cylinder. I think there may be some oil there too. I'm pretty sure it's time to change out the crossover but my question is ... is there any possible relationship to the P0171 code and tiny leak in the crossover such that, over time, it will cause the idle to get screwed up as the computer makes adjustments to the system?
 






I think that is the code I had when one of my injector o-rings was leaking.
 






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