Problems with my MK1!

I've had this problem with my Mk1 for a while now and ive gone through replacing the little things and nothing seems to work. When the MK1 is cold it runs like a dream but as it begins to warm up the problem starts and that is as soon as i drop the revs the car just cuts out, coming to a stop or completly stopping the car will loose all revs and die. Also the car, as im driving, will kangaroo and vilently bounce as if its being starved from fuel, so we have changed the fuel pump and the relay and nothing seems to help. Its got to the point where i cant even get off the drive without it cutting out. I have taken it to a garage that the AA reccomended but even they had no clue. Please help because im without my beauty.

Which car have you got Fuel injection or Carb?
Engine code?
What year is the car?
Do you have a picture of the engine bay?

Have you had problems with the fuel filler neck and have you checked it for rusty holes?
What's the inside of the fuel tank like?

Yup, sounds like dirt in there somewhere, or if its a carby, then there's a few things it could be, but by the sound of things fuel related. If it is the carb engine, could it be the seal in the inlet manifold messing around? Mine did a similar thing, replaced that and cleaned the carb and everything was lovely.

If its the Injection engine, then someone might know more, but doesn't the 5th injector have something to do with running when warmed up?

I had similar problems with mine which have just been cured, Not sure if it helps but here the link to my thread http://vwgolfmk1.org.uk/forum/index.php?page=topicview&id=helllllpppp%2Fclipper-cab-problems