Intermittent running problem

Alright guys and girls

I've got a 1.8 8v Gti which I've been driving every week or two for the past six months. It's ran fine up until the last few journeys where it's developed a problem:

At random times while driving, the rev counter needle will start bouncing around all over the place and the car will really struggle to rev. Then most of the time that will be followed by some pops and bangs from the exhaust so I guess it's getting enough fuel?

It's happened while trying to pull away meaning I haven't been able to get above say 5mph for a few seconds and also while driving at a constant speed, accelerating and coasting. 

Any ideas? 

It's driveable but seriously annoying as when it happens I almost headbutt the windscreen!

Sounds like a bad connection at the igntion coil to me or the coil needs replaced, rev counter bouncing around is linked to the coil i think
ta
baz

As above, sounds like some loose connections, or earth faults.

Wicked thanks!

I'll have a look when I next see daylight outside of work haha

dappy rev counter can also point to hall sender issue, so check the wiring to the dizzy. peel the rubber back to check the wires right to the pins plus unplug it and check the pins are not bent out of shape