Post over on www.fccuk.org I'm a moderator over there.
Just got to quickly say, these are brilliant cars for the money, I've owned two now, and would think nothing of owning another in the future. IMO for £3500 for a decent 20VT I can't think of anything that is as pretty, reliable (NOT built by Fiat), and with such a sweet sounding and powerful engine.
Back to the problem, the late 20v had a VIS engine (variable valve), so maybe this is playing up, and causing it to not rev beyond 5k? Most problems on the Coupe usually trigger the injector light on the dash - is this on?
I always used to take my Coupes over to Powerfiat http://www.powerfiat.co.uk/ , in Essex. A long drive for me from Somerset, but always worth it. Give Roger a call on his mobile 07946 66672 and tell him Fishy Dave put you in touch. Alternatively, register on the fccuk forum and post/search in the problems area.
Cheers, Dave
New owner of BOSS