I removed the fmu and put the fuel lines back to stock. The connection is now leaking that goes from the return line back to the tank right by the fpr. Is there a gasket or washer that is causing my leak or what could it be?

 

Over 60 people read it with no answers. I finally pulled it and found the O ring was bad. The part was .41 cents and took 2 minutes to replace. There is one in the female side of the return line. I bought it at the hardware store so i hope any rubber O ring will work with the fuel.

 

I would have said the O ring, but I just read this, LOL. I don't know if those are a nitrile rubber or Viton, but good luck with it. I know some of the NAPA stores and some others carry an assortment of FI small parts in case your's dissolves.