have a co-worker who's been trying to find a slow evap leak on his 2002 4.7 dak. he says he's swapped alot of vacuum lines already and I mentioned that I'd see what you guys might know.

he's already done the fuel filler cap swap and swapped alot of the vacuum lines, any ideas?

 

Does it make a hissing sound after running for awhile?

 

he said he could hear it out of one plastic t fitting, he swapped that one out plus the lines attached to it. hissing gone but code remains.