Engine Vibrates very bad around 1500-2000 RPM

[Thalomos]

When coming out of 1st, getting up to 1500 rpm through 2000 RPM the engine vibrates very bad. I've owned one of these cars before so i know it's nothing normal.

When i get above ~2000 RPM or so it seems to be fine all the way up untill redline. The car has been sitting for a while, and i've only driven it once as i'm considering buying it as a project car.

Any clue?

 

[DSM90AWD]

When coming out of 1st, getting up to 1500 rpm through 2000 RPM the engine vibrates very bad. I've owned one of these cars before so i know it's nothing normal. When i get above ~2000 RPM or so it seems to be fine all the way up untill redline.

Sounds like the rear balance shaft is 180deg out of phase (all-to-common mistake). There is a plug on the back side of the engine which with the car at TDC can tell whether or not this is the case. Reference the Timing Belt VFAQ (fig 13) for details