i reckon its gotta be either the idle like u said yesterday so maybe have a tweak of that,or its been sat sooooo long that when u drove it over u dislodged some crap somewhere in the fuel line and its clogging the carb?!did it still do it on the way home after it was properly warmed up? get something to clear the fuel line,redex do a carb treatment,maybe thats a cheap option to try out. im sure royston had a problem with his but after a while it seemed to sort itself,which is why i think it could be a gunk build up stopping the fuel going thru the jets maybe when theres no pressure to force it thru,like when ur pulling up to a junction! i dunno tho but it just seems weird since it only happened yesterday after u filled up,maybe a bit of rust in the fuel tank has come away,not gonna take much,bit of grit can clog a jet.