There is generally a test port on the injection rail.Make sure you use only a high pressure tester and proper test fittings.The pressure is quite high and can be a serious fire hazard if not done right.
Check the codes with an OBD2 scan tool.
There is no such part on a Mercury Villager.
yes!
Yes, it should fit.
Buy a manual.
No, there is no "adjustment".
134-a
right above the oil filter on the transmission side of the filter mount
4.2 quarts
walmart
Powertrain Control Module
1995 Mercury Truck Villager Van 3.0L EFI SOHC 6cylThe Spark Plug Gap.032 (In thousandths of an inch)