If that water pump isn't seeping, I would think it would be the alternator. That 3.3 engine is the exact same as the 3.8, and they have proven to be darn near bullet proof with regular oil changes. I too had to replace the water pump, alternator, plug and wires and coil pack. Nothing out of the ordinary. Interesting, my oil pressure guage has been jumping around the whole spectrum since 100K, maybe I too need to put in a new oil pressure switch. But back to my first statement: Is it worth the extra bucks?