My 1994 Chevrolet Astro seems to have a throttle body leak that looks pretty nasty. I am not mechanically adept enough to understand exactly what is causing what looks like a crust of carbon on the throttle body - hoping someone here will weigh in! I believe it could be related to an ongoing vacuum leak on the vacuum hose connecting to the tb - the original pcv elbow is no longer available from GM and a mechanic tried fixing it using a piece of fuel hose in stead - it worked for a while, but it is back to getting severely flooded and wanting to stall when coming to a slow down at intersections, etc. Do you guys thing that "carbon crust" is related - leakage caused be repated flooding? What harm has this possibly done? How do I go about getting it fixed?