breather vac and mixture.

got a mk1 16v k jet.
ive got a problem that i cant work out.
when i start the car from a really cold morning it (starts first time all the time) will rev fine and drive like a normal car for bout 4 gear changes.
then when im at the top of my road this annoying and fuel consuming problem occurs.
it keeps dumping more petrol in when i let off the accelerator.
it kind of blips 300 rpm then slowly goes back to the idle. it runs fine and is fast as, but this is just annoying and makes it sound lame.
ive tryed to find out what it could be and have been reading all the forums a few things pop up like breather hoses, vacs and richness.
oh and ive already changed my air flow meter still no joy.
any help at all or advise
thanks
ed

Have a read of Domain parking page


It may help explain whats happening …….

Like The Cold Start Injector :dontknow: