Truck has tick/ knock but after it warms up, noticed after driving if you put it in reverse the tick dulls down and even in drive it seems to fade out but started getting white smoke on start up, oil pressure, temp light seems to be normal please help

 

5.4?

 

Just a thought
Take a piece of hose and hold it near each spark plug while engine i hot and running. Place your ear near the other end of the hose and listen. If noise level changes and coincides with the ticking noise then check that plug and make sure it is properly tightened. Make sure you clean the area around the top of the COP (coil on plug) before you remove it. If plug is loose it bangs around in there and eventually destroys the threads in the engine head and blows out the spark plug.
Good hunting