Ooo, a 620 ti, a nice family sized car but fast engine. Punching out a bit below 200 bhp.
Might just need a good service. The engine is Rover's own T series. I'll probably get told off for advertising another forum, but you're gonna get far more information if you join up on
www.rover-coupe.com and
www.rovertech.net They are UK based sites and the people on them know the T series inside out.