I noticed that the line running from the purge solenoid to the manifold was starting to dry rot on my truck. I just cut the connectors off with a razor knife and put a new piece of rubber fuel line on the connectors.
Yes if the solenoid sticks it can cause rich/lean conditions. You can unhook the line going to the manifold and plug it so you don't have a vacuum leak, then see if it throws a code again.
The Tow Rig-'06 F-150 5.4l xcab w/ tow and chrome package. 20x9 wheels wrapped with 305/50-R20 Toyo Open Country A/T's ~ custom wired GPS ~ MBRP Pro 3.5 exhaust ~ Saleen grille ~ Carriage Works bumper grille ~ Recon cab lights ~ Viper 5902 w/ window automation ~ More mods planned