OK, where do I start?? '02 Dodge Grand Caravan Sport. 3.3L V6, 58,524 miles on it. Oil change is current, air filter clean etc. Spark plugs changed out 1 year ago about 45K...last week it quit on me. Took it into shop, replaced camshaft sensor and fixed wiring harness (had burnt through near the transmission I believe). Picked it up Tuesday, has ran beautiful since, still running great. Gas mileage seems to be a bit worse though and this morning my check engine light came one. Clicked the key back and forth and it popped up with the code P1684. Any ideas??