Ford settled on a single firing order for v6 engines covering many many years of vehicles: 1-4-2-5-3-6
Cylinder numbers:
1 2 3
4 5 6
(Front of Vehicle)
The firing order for the other size & engine types is also available at Autozone.com in the repair guide under Specifications
http://autorepair.about.com/library/firing_orders/bl-ford-firing-02.htm
For a 1994 Ford Ranger , 3.0 liter V6 engine : ( 5W-30 is the PREFERRED oil )
pistons first with 30 weight oil
5w-30
30 to 45 lbs.
5 w 30
In a 1994 Ford Ranger , V6 : NO , 5W-30 is actually the PREFERRED oil ( I have been using 5W-30 in my 1995 Ford EXPLORER , 4.0 liter EFI , V6 engine for over 18 years now )
Go with 10W-30. Get a 5qt jug from WalMart...
5 W - 30 in the 4.0 liter V6 engine
For a 1994 Ford Ranger , 4.0L V6 engine : The PREFERRED oil is 5W-30 With engine oil filter change ( 5.0 U.S. quarts / 4.7 litres )
1963 390 firing order should be 1-8-7-2-6-5-4-3. dwell 30 deg. timing 5 deg BTDC.
5W-30 is the preferred oil ( that's what I've used in my 1995 Ford Explorer since 1995 )
It is either a bad fuel injector or a problem with a valve in that cylinder