its abit hard to go off without a full detailed description, as in....
what speed are u going when it happens, wot gear are u in
goes it miss and run rough (or studder) or is it simply not boosting
is it only cold nights?
it could be coilpacks, it could be spark plugs (or spark plug gap), u could have a boost leak, u could have a tps problem.... there is also alot more things it may be.....
go for another drive and mentally record exactly wot it does, at wot rpm, and wot throttle percentage, and exactly how the engine is running and abit more help....
otherwise check u have good fuel, u dont have air leak in the intercooler piping and maybe remove ur spark plugs and coilpacks and look for cracks or incorrect gaps