I got a ticking sound from underneath the truck. Its a 1983 chevy c3500 we put a 1998 block and we put a mechanical pump and an intercooler in it (hx40) the other day it started surging and ticking so we put a inline fuel pump on the line up by the fuel filter. The surging stoped but the ticking has not. It ticks back by the fuel tank. But the fuel tank sits on the bed and is fed from the bottom of the tank. Its not coming from the exhaust or from the engine at all, but i feel a strong pulse on one of the fuel lines and it is in sync with the ticking noise. Any ideas? Thanks in advance!