I'm looking at an 02 Aztek and it seems to pop into third is this a common issue or should I look for something else and the awd light is on
Run, don't walk, RUN from it.
I'm being serious. You have a transmission and Versatrak AWD problem. You are looking at major dollars to fix. I've had numerous GM vans with the same drivetrain as the Aztec. I'm a die hard Pontiac guy but the Aztec was/is a P.O.S. The versatrak awd was a great idea and worked well until it had problems. Then it got real, real expensive.
What should the rpm be at when it shifts ito gear on this vehicle
That all depends how fast you're going. Shift points will be lower at slower speeds and higher a faster speeds. However, no proper shifting transmission should ever "POP" into gear.