Engine/Transmission (1998.5 - 2002) Fuel presure Gauge sticking

[Xtremewheeling]

Anyone have trouble with what appears to be a sticking gauge or most likly the isolater? Some time it will only drop to 4lb when engine is off other times works fine when it stops going down at 4 it only goes up to 7-8lb other time 0 up to 12lb. I unhooked the fuel line to the isolater with it stuck at 4lb it didn't move. The isolater is about 4inches long 3/4 in diamater with Ispro gauge. Thanks Todd