Mitsubishi Repair: 97 gs-t problems =(, clutch assembly, eclipse gs

Question
i just bought a 97 eclipse gs-t with 73k miles which was actually pretty good and fast for the past 2 weeks. When i first bought the car, there was this very noticeable shake throughout the whole ride especially on neutral, but not on the higher gears. The steering wheel will vibrate more than a normal car would but the seller told me it's because of the "motor mounts" that he replaced.. so i ignored the vibration since the car had a low mileage for an 11 yr old car and was still clean and nice looking.

after a few days, problems started to show up.

first up, the first gear will pop out to neutral from time to time. The owner said its easy to fix, its just some bearing on the transmission that needs to be taken care of.

secondly, after starting the car.. the idle is pretty rough. it feels wierd because the meter will rev from 1000rpm down to 500rpm and up again and sometimes even lower than 500rpm and will slowly stall out . today, it was the first time that the car just died on me on the highway when i left it running on neutral. i had to pull over to the road and start it again.

Its my very first car that i bought for myself, and I loved it for the past 2 weeks, but now it's really sad to see all these problems showing up. I hope you can give me some feedback on what needs to be taken care of to drive it again normally.

Thank You,
Albert

Answer
Albert,
Heavy vibrations could be due to a number of things.  One of which could be a bad balance belt.  The balance belt compliments the main timing belt and keeps the engine running smooth.  On Eclipse engines, especially turbo engines, the timing belt and balance belt should be replaced every 45k-60k miles.  So your belts may be due for a change.  Bad motor mounts can cause your gears to pop out.  But if it is the 'bearing' like the previous owner mentioned, he may be referring to the throw-out bearing.  If that's the case, you may want to replace your entire clutch assembly, since your mechanic would need to get at it anyway.  

Your poor idling may be related to a worn timing belt or bad idle speed controller.  Your mechanic would be able to determine that.  Either way, to really get your car back to 100%, you may need to invest a little more time and money into it.  
Good luck!