Smoke! Wet Stacking?

[Wally]

Cooled off here and has actually rained. Yesterday I was cruising around at low speeds and once traffic cleared some I romped on the truck. The thing smoked like a Bombed Cummins! Did it a couple of more times and it smoked less every time until it cleared to where I couldn't see it all unless the sun was behind me.
I have always had what I maintain to be a slight miss and yesterday it cranked for about twice as long as normal to start. Never flashed the SES. Seemed to run ok. Although this one has never run as well as the Ally equipped truck I started with. It has absolutely no low end grunt!!
All I get from the dealer is, "it hasn't set any codes therefore nothing is wrong".
Any ideas? Wet Stacking from cruising at low speeds? Anyone else noticed something like this?

[hickcox]

About a week after a similar event took place with my '01 truck, and giving me the old line because they can't re-create the problem it doesn't exist.
Well when it did it again I drove it directly to the dealership and parked it so it filled their service bays with the billowing smoke until they came out to me.
Needless to say they ended up re-adjusting the throttle position sensor, hasn't done it since.