Serious problem with carb

Somethings gone badly wrong with the carb in my Volvo 460GLE 1991 Petrol.
I'm going to have this looked at by a garage but I thought I might ask in
here for opinions as to what's going wrong first.
When I accelerate my car seems to seize up(almost as if the breaks are being
sharply applied) and then lurches forward suddenly. This happens mostly when
giving the gas and mostly when the engine hasn't reached normal operating
temperature. I don't think it's a vacuum leak because this strange stop and
start motion happens at random times.
Any ideas?

 

Sounds like the accelerator pump. when you accelerate the carb squirts
a little bit of fuel in to richen the mixture as you accelerate.. If
it is leaking, you will get a bog when you try to accelerate. Since it
is worse when its cold, it sounds that the plunger on the pump is not
as flexible as it should be and leaks, when its warm the the plunger
becomes more flexible and seals better.

You probably will need a carb rebuild

 

I had a recurring problem with a Fiat where, at random intervals, it
would lurch and then die. Turned out to be the carburettor float
chamber full of gunge from cheap petrol.