"Shake" at low rev and low power

[davegb]

Hi all,
I have a 98 Golf Mk4 S - 130,000 miles. (Apologies for the lack of knowledge, and probably technical terms here...) The engine has a serious "shake" whilst idling, and I've also noticed a serious drop in power. The rev counter "bounces" between about 600 and 1,100 revs at idle - I can feel the gas peddle being pulled from under me. The shake stops pretty much at 1,500 to 2,000 revs.

It will also cut out if I put the steering on full lock.

Plugs and leads were changed about 9,000 miles ago.

Any pointers much appreciated.

Thanks,

Dave.