P0171 Code- Bank 1 Too Lean

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Pork Soda

Pork Soda

10 Year 15 Year
Joined
Oct 16, 2010
Threads
13
Messages
307
Location
Fayetteville, AR
I've been fighting this code for a few weeks. MAF and throttle body have been cleaned, air filter is good, no loose hoses that I can find. Front O2 sensors changed in the spring.

What next? Planning on replacing the rear O2 sensor unless anyone has some insight. If that doesn't work, I'm pretty sure I'm running the original fuel pump, so I'll probably change that out soon, anyway.

I'd appreciate any insight.

Couldn't find a current thread for this specific issue. Please merge threads if necessary.
 
Fuel filter is what I intended to type.
Yes, I have the tick.
 
Thanks Trunk, I'll start with the filter and pcv, maybe throw some more money at it next week. So far I've seen no change in performance or mpg, but the wife doesn't trust me when I tell her not to worry about it.
 
Running into the same issue, it is in the shop right now and they are trying to figure it out. Drives fine, light just stays on and it needs to pass inspection. I will let you know what they find if anything.
 
Just realized that I never updated this post.
The dealer came back with a bad "switch" in the power steering system. causing a vacuum leak. I can't remember the cost exactly, but it was too much. $350?
Since I had already replaced fuel filter and PCV, and I wasnt going to drive around with the light on, I had them do the work.
No more codes, but I've always been suspicious that they took me for a ride on that one.
 
Just wanted to add to this thread based on my experience today. I had my Check engine light come on yet my car seemed to be running fine. The Code was P0171. The first thing I did was clean the air filter and then disconnect the battery to reset the CPU to see if the code would come up again. After starting my truck up it immediately was running like s*** and idled very rough. I still have no idea why it all the sudden did this. So today I went and bought a new air filter, a fuel filter, injector cleaner and electronic cleaner spray. I swapped the fuel filter (which was super super old and gunked up), cleaned the MAF sensor, swapped the air filter, and poured in the injector cleaner. I had replaced my starter a few months back and wanted to make sure that the intake manifold bolts were tight. To my surprise I actually was able to tighten them up quit a bit. After disconnecting/connecting the battery again I started her up. The truck still idled terrible. I drove it for thirty minutes and the light never came back on. The truck actually continued to run better and better and then started idling more smoothly. After about 2 hours I went for another drive and the problem seems to be fixed.

Im not sure exactly what I did that made the difference but I spent only $60 at the auto store and 45mins under the hood. So far so good.
 
The code will come back.

And by disconnecting the battery, the ecu lost its learned idle with your dirty throttle body/plate. It had to relearn a good idle position again. You could have just cleaned the throttle body and it would have idled perfectly.
DenverLX said:
Just wanted to add to this thread based on my experience today. I had my Check engine light come on yet my car seemed to be running fine. The Code was P0171. The first thing I did was clean the air filter and then disconnect the battery to reset the CPU to see if the code would come up again. After starting my truck up it immediately was running like s*** and idled very rough. I still have no idea why it all the sudden did this. So today I went and bought a new air filter, a fuel filter, injector cleaner and electronic cleaner spray. I swapped the fuel filter (which was super super old and gunked up), cleaned the MAF sensor, swapped the air filter, and poured in the injector cleaner. I had replaced my starter a few months back and wanted to make sure that the intake manifold bolts were tight. To my surprise I actually was able to tighten them up quit a bit. After disconnecting/connecting the battery again I started her up. The truck still idled terrible. I drove it for thirty minutes and the light never came back on. The truck actually continued to run better and better and then started idling more smoothly. After about 2 hours I went for another drive and the problem seems to be fixed.

Im not sure exactly what I did that made the difference but I spent only $60 at the auto store and 45mins under the hood. So far so good.
Click to expand...
 
Coming across this issue now too, quite a few years later than everyone else. My air filter is whiter than a baby’s butt, so I’ll be cleaning MAF sensor and looking into fuel filter. Anything else I could check easily?
 
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