1 is definitely a vacume leak, had that happen in my 98 E350, was a black cracked line near the battery that runs with the wire harness.
2 - would second first advise.
3 - Ranger Smith, you have my rig!!
2006 Fleetwood Bounder 35E Trek pure Trike,electric, 50 mile range, 980 miles the get everything runner.To be toad list Done, Ford E450 toad.