Odometer stopped because its electric motor or gear is broken, not related to other issues.
Google: ford ranger odometer gear
Common issue, 1995 and up, and not a hard fix but you do need to pull out instrument cluster.
Try this for starting:
turn key on, count to 3, turn key off
Repeat 3 times then try to start engine.
Each time key is turned on fuel pump runs for 2 seconds, and only 2 seconds, it is a safety issue.
Your '97 should have 30psi of fuel pressure at the fuel rail/injectors even after sitting for a few months.
If there is a leak in a hose or a fuel valve then pressure can drop when engine sits.
Fuel pump running for 2 seconds adds about 10psi of pressure.
So running it 3 times, 6 seconds, should restore lost pressure if that is the problem.
If engine starts better then pressure is being lost.
If you don't smell gasoline then it is probably a valve.
There are 2 on your system:
1. FPR(fuel pressure regulator) is on the fuel rail, the return fuel line is connected to it and a vacuum hose, check vacuum hose for fuel smell, if fuel is there then FPR is leaking.
When engine is off there is no vacuum so FPR valve is closed and no fuel flows out of system to return fuel line.
2. the fuel pump has a built in check valve, when pump is off valve is closed so pressure stays in the system, if valve is leaking then pump must be replaced, it isn't a separate part.
But this won't effect driving because as soon as engine starts fuel pump runs full time.
Check valve is only used when pump is off.
Jittery engine could be low fuel pressure and misfires, it would also cause lean air/fuel mix
EVAP system sucks gas fumes from the gas tank.
It has a large black filter canister usually on rad support, from canister there is a vacuum hose to the gas tank.
And also a vacuum hose from canister to Purge valve and then to intake manifold(vacuum source).
Purge Valve is a 12volt solenoid, it will have 2 hoses connected and 2 wires.
When engine is running computer will activate this solenoid and engine vacuum will suck air/fumes from gas tank thru the filter and into the engine.
Between the canister and purge valve is a pressure monitor on the hose, this tells the computer if purge valve is opening and if vacuum is holding at stable level.
This system can only work if gas tank is sealed, gas cap needs to seal the tank and Filler/vent hoses needs to be crack free and vacuum system hose need to be crack free.
Purge Valve would be the place to start, it has a 2 wire connector, remove it.
It has no polarity so you can hook up a ground and 12volt wire and you will hear it click open, 9volt battery will work as well.
If it doesn't click, open, then replace it.
If it does work, click, then next thing would be to test if computer can send it 12volts.
Hookup Digital Volt Meter to the connector(truck side)
Start up truck, you should see 12volts(14v really) in under a minute, if not then there is a wiring issue.
You could see -14v thats fine meter is just reversed.