Diesel intermediate power loss

[Steve Gas]

Help please not had my 2005 RAV4 diesel long and it’s driving me mad.Its been plugged and shows no faults but clearly has something is a miss happens on acceleration as you change up gears goes flat hold your foot down and after awhile picks up and off you go, seems no set speed or revs but normally happens as you go to third or fourth doesn’t matter if you use low revs or trash it and then sometimes it all works fine. Please help before I set fire to the !Removed! thing and go buy another Landrover 

[Steviev]

Hi ive a similar problem when accelerating in 1st 2nd or 3rd the engine is holding back terribly. This seems to improve in 4th and 5th. Ive fitted a new maff sensor and fuel filter, any ideas. Thanks Steve