K11 issue

My k11 1 litre twister is having an issue. Idle seems fine and it drives fine except round about 30mph 3rd gear usually it hd a kind of flat, judder spot for few seconds then takes off fine after. I did get self diagnosis code for maf. Not sure if it is because I tried driving with it unplugged to see of It was the issue. Anyway I resoldered the throttle body. I'm unsure if properly as it's the first time I have used a soldering iron. Still has the problem. I was wondering to save a fortune if it.possible.to get a generic maf and drill a hole in the airbox above the throttle body to insert said maf and connect that instead?