course of going into limp mode

What is your question?

there is no strange noise sometimes it starts in limp mode then clears other times it starts ok then goes into limp mode at times it runs for miles in limp other times it only lasts a mile or even less it has run for 60 miles with no trouble other times it can be yards.It seems to have started after I had to brake very hard hot or cold it makes no difference to how or when the problem occurs