Ok...... my car 2001 coupe turbo.... it has been making a sort of deep groaning noise now and again when i start it up and leave it to warm up, then the T/C light starts flashing with it, and it goes away after 2-3mins. but it will come back again 5mins later and do the same. the noise sounds like its coming from the back of the engine but thats just becasue im sitting in the drivers seat? i havent a clue what it could be? anybody got any ideas?