This is just for information only!

About 3 weeks ago on the way home from work the check engine light came on. I hooked up the scan tool and pulled a P0171 code, and found out this was a lean burn condition on bank 1. Did some research and found several things could be causing this problem. I continued to drive the vehicle. About a week and a half later I stopped by to visit my mother, and then when I went to start the truck to go home it would fire, but not start.

I decided to change the fuel filter so I released the pressure off the front end of the filter. I did this by pulling the plug off the inertia switch, and then cranking it about 20 to 30 seconds. When I went to remove the feed line from the pump to the filter I still got a spray of gas. I went ahead changed the filter connected the inertia switch again, and then cranked her over, and to my delight it started. I turned the CEL off, but I would still get a yellow light on the emissions ready test. I drove it about a week or so, and now have finally got the green light again. I am also back up to 27 MPG, but it had dropped down to 25 MPG after the CEL came on.

Luckily my fix was the first and cheapest one.

 

I have the same code on my 2000 (2.5l 4cyl 89K miles) and have checked/fixed all the cheap stuff I can think of (new PCV, checked every vac line I can find, sprayed starting fluid around, new air filt, cleaned MAF, etc). found one vac leak and fixed but nothing has helped so far.

after every small "fix" I clear the CEL but P0171 keeps coming back each time after about 30 mins of running.

Your talk of fuel filter (I havent tried that yet) made me think of something.....when you were getting the code, did you have any unburned fuel smell outside the vehicle when you stopped and turned the ignition off? that seems to happen to me when I clear the code and then run the truck. After the CEL comes on again I dont notice the smell so much anymore....

 

I never smelled any unburned fuel that I recall.