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Gasoline......................................
Two things happen when gasoline sits long enough, the good part, the "Go Juice", evaporates.
And the water in the gasoline, all gas has water in it, settles to the bottom of the container, in this case the gas tank, and the fuel pump suck gas from the bottom of the tank so...........lotsa water mixed in.
And when someone says "bad gas" what they are saying is it has too much water in it, causing rough running.
So the good parts evaporated in the fuel system and that leaves behind the additives, which has the scientific term of "Gunk" if I remember correctly.
You need to clean that "gunk" out of the fuel rail and injectors, but with engine running it makes that pretty easy.
Seafoam, or similar additive, will clean out the fuel system, so add directed amount to NEW gasoline in the tank.
The "old gas" should have been drained before trying to start, if that didn't happen then drain it now.
If you already added new gas then add some more and the "cleaner", fill it up all the way, try to dilute the old gas
After you run 2 tanks through engine see how it runs then.
Change fuel filter at that time as well.
Ford used a Waste Spark system, so pulling spark plug wires with engine running won't tell you much.
Coil pack should be fine, 2001/2 3.0l Ranger coil packs did have problems but wasn't pervasive.
So that would be a long shot for a 1999
And make sure you don't mix up coil pack spark plugs wires, they have a "odd" order on one side
1 5
2 6
3 4
Front
OR
3 4
2 6
1 5
front
the 5 6 4 side gets mixed up, 1 2 3 doesn't, lol
1 and 5 share the same coil in the pack, as do 2 and 6, and 3 and 4, so these MUST be matched