There is no reliable way to test them for correct operation. They may look good but still won't work right. Replacement is the only sure test.

 

gotcha...yay..so i went through on maintenance stuff yesterday..drained the separator and cranked it up..for some reason haven't had any issues since then, but i'll keep y'all posted. thanks much for the ideas i'll keep them in mind

 

ok so my problems came back, i unplugged the FCA under the assumption that unplugging it should max out pressure in the CP3, and with it unplugged, idle was rougher and idling up and idling down was much worse, so this leads me to believe that the CP3 is bad/going bad. am i right in this assumption?

 

Could still be the FCA not working correctly even maxed out.

Could also be the rail pressure sensor not reading correctly but hsould have some codes.

The FCA is the cheapest part so it might be worth trying it first.