94 4.0L random engine random shut off

[SplashSonChevyDad]

So,
1994 Ford ranger Splash 4.0 4wd auto
Got it pretty good price, kid loved it, big tires, lots of cosmetic stuff.
Kids had it before us took out all the interior plastics pretty much including dome light, headliner, a pillar trim, visors, etc., put all kinds of crazy lights under it, in the grill,
the ignition didnt need a key, but did need a toggle switch flipped on...
i replaced the ignition, but left the toggle, previous owner said it was for the fuel pump.
fast forward to now, the tach stopped working a few weeks back and then the truck randomly dies, for no apparent reason, going straight, stopping, turning, etc.
then it might go a week and never do it again.
i gave it new plugs, cleaned the maf and throttle body, seemed to run better, but still randomly dies. you wait a min or so and it will usually fire back up.
Do i need the "fuel pump switch", if this is toggled off, the truck will not run.
do i have a fuel issue, electrical issue or something else.
I'm pretty lost here, because the issue is so random and so many factors involved.

Thanks,

 

[franklin2]

I would rig up a 12v light bulb and some long wires. I would tape the light bulb to the windshield, hook one wire to a engine block ground, and hook the other wire to a ignition hot wire to the coils under the hood. See if the light comes on when running, off when you turn the key off. Then run it around till it suddenly quits, and see if the light goes out. Keep moving the light wire around to do different places till you trace it to a certain area.

 

[rumblecloud]

So when you have the fuel pump switch toggled on it does the random Russian roulette routine....
Using the noid light, I'd start with that circuit.

Of course if all things are wired properly, you wouldn't need the switch, but that's another issue you may not want to get into.

 

[SplashSonChevyDad]

yes, it will still do the random die..
i have alot of questions concerning this thing.
Like i said when we got it, you could turn the ignition without a key in at all...
is that why the switch is there? i'm not sure. it always smells rich.
my wonder is if the switch is running too much voltage and floods it out?
or has ruined the fuel pressure reg?
i have a 70s chevy, carbed, and then some newer stuff.
I did work at autozone for 10years from 06-16 so i know about some of this middle ground..
i know the engine light bulb is either gone or burned because its never lit up..
i'm wanting to be brave enough to drive it to the store here and get it hooked to OBD1 if they have it. Just trying to get some direction before throwing parts at it.

Thanks guys for the help so far.

 

[rumblecloud]

Not sure what your financial situation is, but ...

OBD1 Code Reader

I bought mine a year or so ago and it has been invaluable. I doesn't solve your problems, but it does give you a starting point.

 

[SplashSonChevyDad]

I'm definitely going to get one, very soon!

 

[franklin2]

Intermittent is going to be difficult to find, even for the experienced mechanic.

 

[superj]

might be a good idea to hit a junkyard and find another ranger to get parts from so you can work on swapping some of the weird stuff out and getting it back to an original configuration?

i would find out about that switch for the fuel pump first. it might not be for the fuel pump but a kill switch so if you can remove that and get that back to how it should be, that will help with working on it because you have this add on circuit that might just be grounding out when you hit a bump weird and killing the truck