I have just fitted a depo boost, oil pressure and temp gauge, full boost showing at 1.2bar. I have had a misfire under load for a while now and was wondering if this is over boost? I can feather the throttle and its fine, I have done the following to try and solve the problem,

Knock sensor
Plugs,
Fuel pump (hrc) and filter,
Maf(thought it was fixed after this, I was wrong!)
There was new leads on it when I got it!

I've not had time to take it to a specialist as there is none local to me although I think this will have to be the next step!

I don't think I have a leak however I'm going to try and check all pipes and connections on my days off work!

X reg UK turbo, green panel filter, sportscat, 2.5inch ss exhaust remap 257hp it also has an after market bov which I have set to recirc.

Thanks in advance