93 gp se..trans bad?or sensor?

finally got the gp almost ready for the road...had it over a year now...

problem ive noticed is when i rev it up in park, as i get to about 2000 rpm,i hear a click like a relay ...then the speedometer kicks up to about 10-15 mph...release the throttle,the speed comes down and there is a mechanical 'clunk',and the car moves ever so slightly...never seen anything like it...any clues?

another thing is the wipers sometimes stop working...the passenger side stays up on the windshield,and the controls dont work...then,just as suddenly,they go back to normal,usually a day or 2 later...

as i said,ive had it over a year,and have not driven it on the road,so this is all at idle

thanks,jon

more specifically,when i get around 2000 rpm,i can hear a relay or something click,thats when the car actually 'tries' to move forward...doesnt actually go anywhere,but you can feel it try...and the speedo activates...then when i decel,i hear a soft clunk,then the car 'relaxes' and rocks back...the tires dont move,but it seems like everything else does....its similar to putting the car in park,then releasing the brake...its almost imperceptible,but im sure its not normal...

ive checked the motor mounts etc...everything looks fine...no clues???

Trans range sensor, or shift linkage out of adjustment?