Truck dies when started on incline.

So I (as well as many others) have a hard start issue with the 4cyl when the engine is warm. Can't figure out the issue. It always starts, just takes more turns then I would like, and when it does start, it's a weak start, and stumbles for a second or two. After it's running, it seems fine though.
Yesterday, I parked on an incline. Came back 10 minutes later. Had the usual hard start, but this time it died immediately after starting. Tried again, same thing. Went for a third time, and immediately gave it some gas and it stayed running.

Truck had 1/2 a tank, so had plenty of available fuel. Initially the hard start issue was said to be too much fuel going to the engine, and it being "flooded". The fact that the truck wouldn't stay running without giving it gas suggest otherwise (in my non-mechanic head).

Any insight? I also have a P0171 code (Lean bank 1) that popped up about 5 months after the hard start issue began.

 

Maybe you have some fuel vaporizing in the line and your fuel pump has to move more fuel to get it to your injectors?

Or, you have a small leak in your fuel line and it allows the fuel to travel back towards your tank? (fuel pump still needs to move it farther than normal to get it to your engine)

Or, your fuel pump is going bad?

 

I thought fuel pump, but the fact that it starts fine in the morning when cold kind of confused me. It also runs fine, (except for about 5 mins after I clear the P0171 code it runs like crap). I just did about 12 hours of straight driving on the interstate without issue.

 

Maybe your fuel filter or a dirty fuel tank. On the 2005 and newer models that code brings up an air fuel ratio sensor could be that to.

 

Yea, the fuel filter was a thought of mine. It's a process on these 2.7s. Probably going to tackle it next weekend.

Nice truck btw.

 

The FSM shows the following possible culprits for a P0171:
- Air Intake hose loose
- fuel line pressure (bad regulator?)
- blocked injector
- bad o2 sensor (pre-cat)
- MAF
- coolant temp sensor
- gas leakage on exhaust system

That last item doesn't make any sense to me.

Check all the hoses and electrical connections for the above systems. Check resistance for sensors and injectors.