Ford 2005 F350 Diesel engine dies won't start then starts continusely same problem for the last two days. Engine code I am getting P2291 6.0 Lemon Diesel

it may be from the STC fitting on the back of the high pressure oil pump or possibly the branch tube o rings have worn. the branch tubes are located under the valve covers and supply the fuel injectors the oil they need to perform their power stroke.
and check the intake and the turbos.

The Check engine light is the first place to start. UNFORTNUATLEY the code readers that the A/P stores have for sale and use won't read Powerstroke specific codes. You need to take it to a shop that uses a code reader that will or the Ford Dealer. Just a guess, but if your truck has the "flly by wire" throttle pedal ( no cable), then I would suspect the throttle pedal validation sensor. There is a known issue for a "dead spot" in the sensor in the go pedal assembly.

when was the last time you changed fuel filter. and are you running bio or reclaimed fuel?

The exhaust back pressure relief Sensor is taking out the idle computer ?????? A wiring diagram isn't going to help , you need a diagnostic flow chart or as ford calls it , pinpoint tests for that DTC . Your best bet , take your vehicle to a qualified diesel tech .

I had this same issue and luckily my F350 2006 was still under warranty. Basically there is a high pressure oil system that has a tendency to leak internally. You won't see any oil leak. When cold the oil has enough viscosity to keep the pressure sensor from not allowing the engine to start. When the engine is warm the system doesn't reach required pressure to allow the engine to start. In short it's a Ford dealer repair. Good luck.

first check all fuses.replace all burnt fuses check the big main fuses in distribution box in engine compartment,if this is a diesel engine.I would start looking at a direct injection module 100% its usually located on driverside inner fender 2"x8"x10" dimensons

Bad Injectors most likely. I have a 2006 f-350 and was having the same problem. I ended up changing the fuel pump and 4 injectors.

diesel or gas engine. if you have a power stroke, look at powerstroke.org

I have a feeling you got a wholed of unleaded fuel or bad fuel
I drive a diesel box truck the station I always took it to the fuelman put unleaded in the diesal tanks and the truck just died it had to have the gas tank completed drained and cleaned out but also ask yourself how many miles are on it and when was last tune up and if you live in a cold climate I recommend a heater block plug

It sounds like it has a high pressure oil problem. does the oil pressure gauge come up while cranking? does it start when cold and not when hot? any check engine light?