Hey guys, i drive a 2000 Monte Carlo SS and im having some troubles. the car has 69,xxx miles on it. I'm not the gentlest driver in the world, but i do take care of it, its always had fluids checked and regular maintenance preformed. my problem started within the past week.

 

Sorry kinda posted that before i was finished typing. Anyways now my car is running strange. at about 2000rpms at about 50mph the tach drops to about 1500rpms, (thats not the trans shifting) then when i hit the gas to bring it back up to 2000rpms the car starts to shake slightly and you can see the tach jump rapidly between 1600 and 2000 rpms. ive been told it can be anything from the trans slipping, to spark plugs, to fuel injectors. i was just curious what you guys think it could be

i know its hard to explain what is happening so i took a video

http://www.youtube.com/watch?v=OH3lrHd1Q9A

the car does it at 0:45 , 1:15 and 1:54 in the video.

Please if you have any ideas or tips on what this could be let me know,

thanks
Steve