I have a 2000 GP GTP with ~91K miles and I have codes P0401 "insufficient EGR flow" and P0440 "Evap system fault."
The codes seem to be connected in some way because I've made a few changes and after every change both codes go away only to return soon thereafter.
I started by cleaning the EGR valve, replaced the PCV valve, replaced the fuel cap, replaced a vacuum hose that goes from the throttle body to the canister purge valve, and finally replaced the canister purge valve. I've also inspected all vacuum lines from the EVAP canister to the engine compartment.
I'm wondering what would cause both codes to be joined at the hip since like I mentioned, they come and go in pairs. What else should I inspect?