I have a 92 2.3 ranger that I rebuilt bottom and top, this truck has always been really dependable, until about six weeks ago when it suddenly began to die at random times.

After checking pulling codes and some testing I found a bad MAF, thought that solved the issue but it continues to die after warming up for a time.

When cold you can start it and it runs normally (idle air control works fine) it will run normally until it gets warm then it will just die, sometimes it will start back up sometimes it will not.

I pulled off the intake manifold, replaced, IAC, TPS, serviced the EGR, replaced the fuel injectors, same thing starts normally when cold, once it warms up it will die then run rough until it dies again.

I am stumped, I thought it might be related to fuel supply, so I connected a fuel pressure testing at fuel rail, 30 psi, at idle, up to 40 psi at 2200 to 2500 rpm

When the engine dies fuel supply is good, at 30 psi, replaced the fuel filter just to be sure there was no intermittent restriction issue.

Anyone found a similar issue and figured out the cause?

Ran codes, got a 118 koeo. got a 998 key on engine running.

At this point my only thought is that either I have short which is killing power to the ignition or the Crankshaft position sensor once warmed up stops sending a signal, but that is just a wild theory.

rebuilt engine at 153,000 now at 188,000 and until six weeks ago ran perfect.

Any theories or practical experiences with a solution would be greatly appreciated.

I have replaced ignition module, MAF, TPS, IAC, Edit, also replaced both coil packs, after finding crack in front coil pack, (was shorting to ground)

 

It reads like an ICM(ignition module) issue

Did you use the grease on the back of the ICM when you installed it, that is the heat sink "gel" to keep the ICM from over heating, its a must have, or you will get what you have, stalling and no start after warm up
And since its "new" it may be faulty, new now-a-days just means NEVER EVER TESTED, no longer means "it works"
If it under warranty replace it

 

I cleaned the heat sink, used dielectric grease, honestly, I suspect that the original part was actually fine, (after a few weeks of trying to figure out what was wrong, I broke my own rules of ordering no parts until you know they are bad)

I am down to two or three possible issues, my next step is to try to determine if the ignition system is loosing power when it dies, after that I will pull the computer and see if there is an obvious failure point, but seems like if there was a failure point in the computer the truck would not
start and run normally until it warms up, its a real head stumper.

using a hand held code reader, (because the dash lamp does not light up or it is an indication that there is a problem in the computer)

One thing I did find odd, is that the reader manual states that when running the KOER test, the system should show number of cylinders, it does not it shows 0 where it should read 4 another mystery.

Thanks for taking time to reply appreciated.