Hi. i have a 1990 vw polo 1.3 saloon. for years it ran rough, kept cutting out etc. i think the original carb was the pierberg which i understand was problematic. i got a new weber last year but it's still not running as well as i expected £500 later. its lumpy. when you're doing 30 in 4th it judders. that smooths out if you pull the choke out a bit. somebody suggested an air leak. please does anybody have any ideas?

is it mounted via the original style rubber base?  they can fail often 

 

otherwise good check round that the fixing are tight , any vac hoses are in good order etc

thanks for your reply. not sure. any idea where i could get a quality replacement base in case it is that?