Sometimes white smoke starts coming out of the tailpipe. This last for about 3 minutes and then stops. Right after the smoking it pings when I accelerate. This stops after about a mile. The truck does not loose power or hesitate. It just blows a large cloud of white smoke.
White smoke is generally related to coolant burning, are you losing any coolant?
Pinging can be from a multitude of reasons causing a lean condition. MAF contamination, excessive build up of carbon to name a couple. Thry an air induction service for the pinging, It's good maintenance regardless.
I would try what I call an air induction service.
I like to use castle hydroblast. You spray it into a vacuum line such as the brake booster line if nothing else is accessible. Full spray for 3 minutes, stall the engine with it or have someone kill it while your spraying. Let it set for a few hours then take for a short drive in low gear, revving the rpms to help break it up. First use Castle cleansrite to clean the throttle bore. Try to get the throttle plates scrubbed good with a brush, while your spraying. Use a rag to wipe the carbon out between brushings. Seafoam is another good product, but smokes a lot.
IF you can't find Castle, here is my rep's email: robw@castlepackspower. Com