Dead pedal with lottsa blue smoke

[coldwar ranger]

Hi Boys:
Been a while since Ive been here, but Ive been having a problem lately. While cruising along at low RPMs (in town at about 15mph and congested freeway at about 40mph) I lose all power and get lottsa blue smoke. When I let off the pedal and let the engine get its thoughts together, it comes back fine. If I go WOT right after this, it goes like a bat outta hell. This has happened about 10 times in the last month. I changed the fuel filters but still have the problem. Not sure if I should take it in to see if it is throwing a code.
This is a 04 Crew Cab with 86,000.
By the way, this truck has been a CHAMP for me. No major problems. The only major expenditure Ive had is front end ball joints upper and lower. I pull a 13000# skid loader and trailer on a regular basis.

Thanks