There's no need to replace knock sensors, and there was never a 3.6 engine.
In the fuel tank
The Villager PCM is located far under the dash, near the firewall. It requires a fair amount of disassembly to reach it, so I'd suggest actually making sure there is something wrong with it before attempting it.
The trim pieces are different.
no
It's on the passenger side, at the very bottom, in back.
This is a bolt-on part. I suggest you take it to a shop if it's not obvious to you.
Yahoo Groups has a very helpful group; villagerquest. It is here you find the answer(s).
The blower is controlled by the blower switch, blower resistor, and relevant power relay.
I have a 1999 Mercury Villager Estate, with the 3.3 liter V-6. I don't drive the van only in town, I have about a 10 mile trip at 55 - 60 mph to and from work, with some other short trips. I average about 17 mpg doing this, on the highway I get about 20 mpg. Hope this helps.
Up/Down arrow key.
Do you have an owner's manual? If not, purchase one from a dealer as the reset procedure is not difficult to do but, lengthy to write out here. If I recall correctly, all U hav 2 do is dial up a station and hold in the appropriate button you want it set on 4 a few seconds until it "beeps". Then it's "locked in"!
The speed sensor is at the top rear corner of the transmission housing. It's a long reach from the top. There is one screw holding it down.