Originally Posted by yamahaSHO
Are you talking about the little drum looking things next to the strut tower? Those aren't check valves.
No, the stock fuel pump has the check valve on it....and I believe walbro's also have this "built in" check valve. If you don't have one, it could be the cause for the pressure drops.
Here is a link of what I'm talking about
Look at pages 11 and 12