Ok i'll try and explain my problem as best as possible...?

I purchased a 1989 Mk2 GTI 16v Golf last November 2003 the cars been great until the otherday.
I started the car the other morning and it was idling around 1000RPM coughing away and it sounds like it was going to cut out but didn't. As i was driving the car down the road putting the foot flat to try and warm the car up it sounds like a Subaru and there was no power, then after a couple of seconds the kicked in and it was fine. Its switching and i'm not sure what is causing this?
Any idea's would be great...
Thanks
Garry