Running a bit lumpy!

drove my cabby gti to work this morning. everything ok at normal revs. If i get a bit carried away and boot it a bit when i change gear and get back on the gas the car hesitates at first then gets going again. at worst it feels like it's going to stall at best just a bit lumpy.

thoughts?

Have you checked the usual culprits, plugs, leads,dizzy.
Has it been serviced recently? Check fuel and air filters, fuel pump, accumulator and injectors

had a quick look, leads, dizzy, sparks are all new last winter. no leaks around fuel pump or injectors. i'll have a look at the fuel filter see if thats ok.

New fuel pump, started hearing whining coming from the fuel tank. all sorted now.