am I losing it or are the fuel lines to my fuel rail 3/8 firewall side, and 5/16 on the pressure regulator side?!, I've been chasing a "cough" while under light acceleration, a couple of other gentlemen here suggested looking for a vacuum leak first which I did look and found a slight leak at my brake boost hose into the upper manifold.....fixed it running much better but cough came back after a day, its very sporatic and infrequent now, and I replaced the rear 90 degree fuel line connection on the rail with a new 3/8 quick connect (it was leaking), the other hose connection is obviously a 5/16 and my local parts houses don't shelf a 90 degree "splice in" 5/16 quick connect, I was hoping this would resolve my "cough", but I'm thinking maybe another vac leak or possibly a fuel pump issue starting to show itself, it is a non AC Delco pump bought a year ago from Ebay, one last note I can hear more than feel or see in the tacho very slight surging at idle, everything has been changed or new....i.e. motor, sensors...MAP, TPS, IAC, fuel pressure reg, filter, injectors etc., etc.....it couldn't be I painted the motor gold and red for the 49ers could it?, anyway I could use some input, thanks

 

You are correct, 3/8 Supply line and 5/16 return line for fuel