i would check for boost leaks too. if you got a boost gauge plumped in check there, the intercooler d seal and jubilee clips on turbo to intercooler pipe. Boost leeaks cause poor mpg as it pumps in more fuel but losses it through the leaks. since sorting my boost leaks and with my economy mods like hdi box and retune i've seen easy 60mpg this week
Don't worry about what I'm doing, I want you to worry about what you're doing