Road Trip Check Engine Advice

[josiahsm02]

Hello all, I'm currently moving from Oklahoma City to Salt Lake City to start a new job. I have about 300 miles left and I am currently staying with some family in Colorado until Monday.

I drive a 2001 2wd ranger XLT with a 2.3L 23NS duratec I4 engine and a 5 speed manual transmission.

About 6 months ago a friend and I changed out the spark plugs/wires and he cleaned the mass airflow sensor with throttle body cleaner - burning out the sensor.
Immediately after the truck started running rough. Turns out the cylinder one plug was faulty, so I changed it out alongside the mass airflow sensor (a cheap one). Since then I repeatedly get the code P0171 (system too lean, bank 1 https://mechanicbase.com/trouble-code/p0171/ ). I also get P0455 pretty often, but I'm not sure where the leak is (Large evap leak, https://www.autozone.com/diy/diagnostic-trouble-codes/p0455-evap-system-large-leak-detected ).
Since then I have changed out my:
-Upstream O2 Sensor
-Fuel Filter
-Fuel Pump retaining ring (was cracked)
-Fuel Neck (rusted and cracked)
-Checked for vacuum leaks multiple times and found none

None of these have fixed the codes permanently. However, I've noticed that if I add fuel injector cleaner to my gas it helps delay P0171 from coming back. The plan for the road trip was to just use a fuel injector cleaner whenever I got the code.
My truck is pretty loaded up, and has a small engine, but it did pretty good the first 400 miles or so. Then as I got into higher altitudes and further into the trip I think I started to notice a loss of power, as well as P0171 regardless of fuel injector cleaner. Going up steep inclines I struggled to even hit 40mph

About 600 miles in I got a P0008 code (usually a timing chain issue, https://www.autozone.com/diy/diagnostic-trouble-codes/p0008-engine-positions-system-performance-bank-1 ), which I am worried about. However I didn't have much choice except to just keep going. I turned off the code to see if it would come back again. At that time I also started putting 88 octane instead of 86 hoping it would help on the mountain passes. I drove another 200 miles and haven't got the P0008 again thankfully.

I'm new to working on engines, and have never done anything nearly as difficult as a timing chain. Do you have any advice on what could be causing the issue, or how to prevent P0171 (fuel mixture too lean). I am planning on replacing my mass airflow sensor with a quality one and eventually replacing my fuel injectors too see if that fixes the trick.
I'm hoping the P0008 code was just a fluke, but thats wishful thinking.

Also, despite the mountain driving I've been getting around 29-31 MPG. I feel like if the P0008 was genuine I should be seeing a decrease in mileage.

I really didn't want to make the road trip while I was still getting check engine lights occasionally, but I'm broke and didn't have much of an option.

Sorry for the lengthy post, thank you in advance for any advice.

Here's the truck with all my stuff lol

 

[pjtoledo]

your symptoms sound similar to my 2005s issues a few years ago. cylinder 1 lost compression and let oil past the rings.
the O2 sensors see the poorly burnt oil and think the fuel is too rich, then cutback on fuel enough to cause it to run lean.
I would pull the plugs for inspection. if one of them is oily/dirty run a compression test.

 

[901wd#2]

My theory on your lean condition related to the large evap leak. It’s trying to suck fumes in to enrich the mixture but it’s just sucking air instead.