Misfiring engine when cold - injector sticking?

[steforrest21]

Have a b8 1.6d , had engine management light come on a few months ago , mechanic said it was coil pack number 3 when scanned, replaced all 4 coil packs anyway. (But did drive car for 6 weeks with light on).

Got car serviced when coil packs replaced, now misfiring when really cold mornings, mechanic took the car last week and started it every morning , it didn’t misbehave till the final day he had it then he spotted it, scanner didn’t pick it up but he said injector is sticking.

Told me to run an injector cleaner in with the fuel, can anyone recommend one please? Also said to replace fuel filter in a few weeks too.

Anyone else had this happen or have any ideas

Thanks

Steve