Impreza 93, FWD, 72Kmi has developed strange sound couple weeks ago: Rather low-pitched, "tapping" or "knockng" that sounds like it is synchronized with the engine (as if a small hammer on a wood, fairly frequently and at some distance). The sound comes from under the hood (seems to be closer to the passenger side). It is heard only when accelerating (the harder, the louder the sound), and disappears very quickly as soon as I take foot off the gas pedal.
Oil level is OK, during the last weeks that the sound appeared milage remained the same, oil is not burned, other than this extremely annoying sound, the car feels normal.
Any ideas what this might be? Someone told me I might be killing the engine by driving it without fixing the problem. How likely is that? Unfortunately, I will not be able to get to the dealer this week, and maybe even next one...
Thanks a lot for any hints!
DK