t230 going into limp mode

[stev62]

Hi all
I,ve a t230 tdci 90 on 04 plate, had a few issues with the van going into limp mode over the past few months
i changes the pedal about 3 months ago, no effect, then changed the cht sensor about two months ago, that had an effect, what happens is when the engine is warming up
after about 2 or 3 miles or so the temp gauge drops to nowt and the engine goes into limp mode, if you stop and restart its ok for another minute then cuts power again,
only when the temp gauge starts to get off of cold is it ok, and never happens on a warm engine. could it be a faulty sensor? stat? takes a long time to get warm
i cant afford the time and money to take it into fords, its 100 quid just to put it on the machine
any ideas anyone, as i said when its warm never a problem, even gives me 470 miles to a tankful!