Hi new to this page just wondering if any1 can help, im getting a lag mostly in higher gears and between 50-60mph and its hard to go faster, its as if the engine is choking and something is wanting to pull it back, a local garage put the computer on it and it came up saying boost pressure fail but he cant seem to find it, turbo is fine and egr valve is clean as a whistle... any help would be much appreciated thanks