My 81 caddy is getting lots of air bubbles out of the dicharge line from the IP, there are no bubbles in the inlet line while it is running but some come out of the IP after the engine is turned off and travel backwards towards the fuel filter. There are no external leaks on the IP or any lines and all fitting are tight. It starts after about 10 seconds of cranking even at 10 degrees F. and otherwise runs great. Any help would be appreciated