WHEN DRIVING THE TRUCK DOES NOT HAVE ANY POWER AND BACKFIRES

do you have a check engine light? are there diagnostic trouble codes? That should tell you what's wrong.

try replacing your PVC valve or EGR valve also check for vaccumm leaks

Is the check engine light on, and have you checked base fuel pressure with a gauge ?

Check the timing, if not set correctly you will experience this along with maybe some trouble starting.

Have you checked the fuel pressure under a load, low pressure will cause these symptoms. The test port is on the top of the engine in the fuel supply rail to the fuel injectors, the fuel pressure test port looks like a large tire fill valve. You will need a fuel pressure test gauge to do this test (about $20), the pressure must be watched while you accelerate, it should never go down on hard acceleration just up about 6-8 PSI

I would suspect a burnt valve. An engine compression test will verify this.

Change fuel filter and air filter .

whats make model and year engine size

check the air intake or manifolds gasket /seal

i think your timing jumped.i had a truck that did that and had to put in a new timing chain