this happend to me mate turned out to be the battery, got it changed and shes fine now ,, in this weather if your battery its not 100% you will get probs,, you had your alternator changed too? make sure that it was a 75amp on not a 55amp, cuz with the turbo it needs the extra amps for things like fogs and heated screen etc.if its not your battery will struggle. worth a try?? let us know how is goes