1341 g40 intermittent full boost

[rhyswills1]

Hi all just finished rebuilding my g40 1st time I've taken it out and it occasionally cuts out when off the throttle on over run but starts up again straight away and it is only running full boost intermittently but if you come of the throttle and back on it sum times get full boost back again we'll i presume it's boost or wether it's just holding back :s car has been sat being rebuilt for nearly a year.I'm possibly thinking map sensor :/ any help would be much appreciated

[gaz g40]

Bit more info needed. Take it its a turbo setup? Have u changed anything electrical wise to get it running?

[rhyswills1]

No mate it still running a g40 charger

[rhyswills1]

Taken it for a good drive today, when it's playing up I'm getting about 8psi and when I can get it to boost properly I'm seeing more like 13-14psi but going flat on the throttle it seem to hold back Slightly