Engine problem

Hi there, I have a disco 4 and it MAP - mass or volume air flow correlation bank 1. I've replaced both the air flow sensors that come out of the air filter box, also replaced the map sensor onto of the engine. Then cleared down the fault code, but the next morning the same problem came up.
Can any please shine some light on what it could or might be?
Kind regards
D4dogunit

Leak from the induction pipework or intercooler.

Hi there thank you for your reply, that was helpful. I've also just seen an old friend who showed me the problem, a small pin prick thats causing the reduced power