Pump Timing

[nfox]

My brother test drove a 95 auto ctd, and the temperature here in iowa is 20* outside. He got the truck started and you could barely see for all of the white smoke. It run for about 5 minutes and he took off down the road and it smoked really bad white, and he pulled over and said the truck has no power at ll it will barely go 30 mph. So we let the truck warm up a bit longer and it seemed to get better the more it run. It also had a sort of clanky sound when it first strated. Is it possible that the pump timing could be off a long ways? Any other things to check. Truck is completely stock.