Ok. 98 ranger v6 4.0 automatic. It's had intermittent starting problems the whole time I've had it, for 4 years. Most of time it just needed a little starter fluid boost a couple times a year, always in the summer.

This year I began having more starting difficulties, and eventually it's escalated to either requiring starter fluid or just not starting. So I have been doing the starter fluid method regularly for a month now. I know it's not recommended, btw.
. **edit** When I drive steady without stopping for a while, like 30 minutes or more, the fuel gauge will creep up. I'll usually have at least half a tank of gas. Sometimes it will finally the way up to the full red part of the gauge. I'll continue to drive and it eventually drops down.
So, here's what it does. The motor turns, sounds great and strong. Always starts up after starter fluid in air intake. Proceeds to run (*pretty*) good. Starts easily several times after. Like when I'm in and out on errands or something. Usually over an hour to several hours. (Combustion on ether residues?)

***as far as running good: only recently it's developed a chugging hesitation, usually at about 40 or 50 mph. Sometimes several chugs in a row. And I think they're becoming more frequent.
On random occasions (today too), ill see white smoke from the exhaust. And usually smell a weird chemical burning smell from the exhaust, like acrid and pungent.
There are no engine codes on. The rpm dial doesn't move when engine is turning (I think that's an indicator of something if it does).

Here's what I've done. New spark plugs, fuel filter. I checked inertia switch on passg floorboard, it's not flipped. I half pulled fuel pump relay while running and got a bunch of clicks which seems to indicate it's good.
I've currently got a fuel pressure test, rented from parts store. So, while it was still high off it's ether residue, i pulled the fuel pump relay and turned motor for 20 seconds, to relieve fuel pressure. Hooked up gauge, and WITH RELAY BACK IN, KEY ON, NO PRESSURE.
(something tells me that means something).
So, turned motor, engine started. The pressure got to and leveled at 42 psi. Turned engine off and pressure stayed there.
I've got a list of parts, relay, sensors, tests. But let's cut to the chase... fuel pump? Or that little $24 relay.... whatcha think

 

What I would be concerned with is what you had to say about the white smoke and smell from the exhaust, this is a indication of antifreeze getting sent through the engine.

This means you should check the coolant level and perform a cooling system pressure check and make sure it holds the rated pressure.

You can also check for Hydrocarbons in the cooling system with a block tester kit which could be borrowed from a parts store like Pep Boys, Autozone,ETC you get your money back for the tool once you return it but you will have to buy the indicator fluid.

A compression test will reveal a obviously bad head gasket or cracked head, yet your symptoms does not seem like the compression levels have been effected that much yet.

At this point we just need to make sure all six cylinders are producing compression properly and not introducing coolant into the engine.

Make sure to check the coolant for signs of engine oil.

As far as the fuel pressure how long does it hold pressure?

With your truck off and fuel pressure gauge connected, turn the key on the pump should power up briefly then turn off write down what pressure you get.

Then while cranking without adding secondary fuel the pump should come on and provide fuel pressure if the engine just cranks and cranks and does not start write down the fuel pressure.

Turn the key off and write down the fuel pressure after the truck has sat for at least 1/2 hour.

You could also get a noid light set from the parts store to connect to a injector connector while cranking to make sure you are getting injector reference pulse. ( the light should flash while cranking )

let me ask you about the smell before you go and pick up tools.

Is the smell kind of sweet or does it smell like rotten eggs?

 

First, starting fluid(ether) doesn't hurt a 4 stoke engine, gas or diesel

2 stroke engines need oil mixed with the fuel, so starting fluid can be bad on its own since there is no oil added for lubrication, thats where the "starting fluid is bad" comes from

Ether has a lower ignition point than gasoline, so requires very little compression(heat) to get it to ignite with a spark, which makes it a good starting fluid.

My suggestion would be to put some gasoline in a spray bottle
Remove air tube from intake, open throttle plate and spray some gasoline into the intake
Now try to start the engine
If it starts then compression and spark are OK
If it still doesn't start then low compression or weak spark is the cause of no start

If it does start then your fuel delivery system is the problem
Could be computer is not "choking" the cold engine, not adding enough fuel, to take this off the table replace ECT sensor, $6-$8, it is on the lower intake above thermostat housing
It is the TWO WIRE sensor, not the 1 wire SENDER use for dash temp gauge, they look similar and are near each other on lower intake


Yes, did the fuel pressure hold?
Fuel injection pressure should, in 1998, stay above 25psi for MONTHS, not minutes, hours or days, MONTHS
If not then turn key on and off 3 times, then try to start engine
Fuel pump only runs for 2 seconds each time key is turned on, in system loses pressure over a few hours then turning key on and off a few times should get enough pressure back to start it