1997 Chrysler Town and Country HELP Won't start

3.8L Recently bought this van, day after purchase would not start. Kept messing w/ it till it finally started & has been on & off. Check Engine light on error code P1495 (purge solenoid canister). Everyone pointed to fuel or camshaft sensor. Changed cam shaft sensor started backfiring then o.K. But still no start. Had fuel pump & filter changed, camshaft sensor changed again, along w/ purge solenoid canister. Seemed o.K. But again let it sit over night no go in the morning. This afternoon wiggled spark plugs she started right up & a few times after that. Pure Luck? Talking w/ a friend who asked if it was hard to turn the key in the ignition & why yes it is. Could it be the tumbler or ignition switch? Any other ideas? I have spent all my money on parts that I did not need kind of feeling like an idiot right now but I need something that makes sense. The other hunch is the cam sensor towards the firewall that has the magnet to detect the camshaft is turning.