Only at night can I see smoke on pull. I have noticed something on this engine that I did not see on any other. When pulling at around 2300 or 2400 with a load, up a hill, at WOT, there is a normal amount of smoke in the headlights of a following car. But when I shift to the next gear, there is a large puff of smoke as the engine shuts down for the shift.

Is this normal? I have not seen it before.

 

Mine does this also, it is odd, that the only time I see smoke is when shifting, and usually only on the shift from 3rd to 4th, and 4th to 5th. I never see it in 1st or 2nd. I would expect smoke when putting foot down when rpm are less than 2k, but I can never see any smoke in this case, only when running it up to 2500 to 3000 rpm do I see it.