Been seeming like after my 1999 D2 has been sitting, (parked outside in cold) there is a lack of power when I first run the engine. I will shift into drive and it seems like it will rev to 2-3 thousand RPM's before power gets to the wheels After that, however, there are no issues. Is this just from the cold? or could it be something else?

 

Sounds like your transmission fluid might be low. It can take a few moments for the pump to build pressure if that's the case.

 

I literally just addressed this problem with my 04 D2. Same symptoms your having accept after a week it got so bad that the truck would not move at all. Either your transmission fluid level is low and or really dirty or the transmission filter is bad/clogged. A full transmission fluid and filter change resolved things with my truck and now she drives good. Your best bet is to follow suit ASAP before damage occurs. Also inspect the transmission intercooler lines for any leaks and ensure everything it firmly in place.