Polo GTI W reg - Running flat :-(

[Callum]

Hey Everybody, love the forum, I tend to read a lot but not write much!!

Just wondered if any of you chaps have experienced the problem I've got:

I've just done the cambelt on my Polo GTI 2000, all timing marks aligned perfect, new tensioners, but seems to be running flat... Of the mark is ok, just won't rev as well, and some times is a pig to start.

It's really driving me nuts any advice???

Thanks in advance

Callum