I turn the key to the run position and let it sit for a few minutes then the relay box starts clicking. It clicks for awhile then when it stops the truck starts right up. If I try to start it before the clicking stops it won't start. I have change the main computer the relays and the fuel pump. Does anyone have any idea what could be causing this problem? It seems like it just isn't building up the fuel pressure it needs to run but once it does it runs great. It usually runs great for the rest of the day after I get it started.