I've been going nuts over this.
2 years ago I was paid to remove this Bronco from my moms place, all she knew is it "stopped and would not go" so she didnt want it anymore....
I get it home and find the A/C compressor had locked up, replaced it and it ran fine for a while.
Now its new thing is, when the outside temp. gets above 80 it wont run for more than 20 mins before it starts to lose power, missfire, back fire, sputter and die. will not restart for at least an hour sometime more depending on how hot it is out.

I have replaced these parts having to do with ignition, and fuel delivery:

cap and rotor (motorcraft)
spark plugs (motorcraft)
plug wires (duralast)
fuel filter (fram)
air filter (k&n)
fuel pressure regulator (motorcraft)
ignition coil (duralast)

The engine doesnt overheat, i've cleaned the MAF sensor, cleaned the thottle plate, used injector cleaners, used seafoam thru the intake to clean carbon buildup, the oil is changed regularly, checked resistance on all but a few sensors ( those i could find spec listings for). i bought a manual it has very limited info on my model bronco. as i understand it this in the only year model that has an OBDII system on it. My final suspect in fouled up parts on this thing is the distributor, but i'd like to know what (if any ) sensors are inside of the distridutor, and if so, could that failing sensor(s) exposed to heat cause these problems?
Any advice would be greatly appreciated, I love this damn thing and i wanna drive it again.

 

Check codes, esp. an ODB2 should be able to tell you exactly what's going on even if you don't have any CELs or anything.

 

Three possibilities come to mind but pull codes first. You are correct in the 96 and OBDII engine control system. If it has three areas of codes like the predecessor KOEO,CM, KOER you may find codes for the stalling issue in CM (continuous memory).

After you have the code numbers please check back with us.

 

a couple little things i have had trouble with in the past after a running engine started to die on me.

replace the heatsink compound on the module on the distributor.

replace the relay for the fuel pump

i would feel around for warm electronics and wires right after the engine dies on you.

 

As for the above link and the issue with the heatsink on the distributor...

That is what was wrong with my bronco. My truck would only stall, stutter and die when I had been driving longer. For example, i would be trail riding in the mountains and it would run fine, but after awhile it would start to die, and would be difficult to keep it running, and sometimes it would die and I could not start it until I let the vehicle sit for 30 min or longer. I tried several things and nothing worked. I ended up just buying a completley new distributor. Then I read a link on FTE that stated the following

To determine if it is the distributor is the cause, one person advised the following. When your vehicle starts to sputter and die, shut the vehicle off. Take the distributor cap off and take a can of compressed air, hold it upside down and spray into the distributor for a few seconds. Replace the cap, and try to start.

The above is what someone else suggested. I was afraid to try it because I was afraid that spraying ice cold fluid (from the canned air upside down) would cause something to crack due to the extreme temp differences. So I ended up just replacing the whole distributor and never had the issue again.

So try the above and your own risk. you might also try just blowing air into the distributor for 30-40 seconds, that should cool it enough to know if you've found your problem

 

I've dealt with 3 randomly dying fords. Two were the ignition module. On my 90 it was the ignition pickup in the dizzy.

 

Things that come to mind in dying Fords , one was a 1979 f-150, would quit on the interstate(hot ) Some owner before i had put an undersized battery in it and it would overheat n die, Changed the battery ---no problems , Second was my f-150(1985) mmmhmm ignition module , no it didnt just go dead, it was shorting out ---when cold would run good---hot would short out Good luck TR

 

I would not suggest a remanufactured distributor as you may get someones same problem as yours when the stator gets hot. I'm not sure they replace them if they test OK. Mark EVERYTHING when pulling the distributor and take it to a rolled pin punch and press to get the marked gear off. Install a Motorcraft stator.

Start shopping for a black Motorcraft ICM. The one off a 6-cyl Taurus works great on my 5.8.

It is not impossible, just unlikely, this might be the start of the capacitors failing on the PCM. My transmission had issues after the intermittent dying. I had the PCM rebuilt at the sme time as replacing the stator so really don't know what corrected the stalling.

 

Ok, after having the battery cable off for so long while making repairs, the computer has reset. (no codes) I did rebuild my own distributor, replaceing my hall\fx sensor, and bearings, runs 10 times better, but still sputters and stalls after driving a hour or more in high heat, this model of bronco has it ignition module mounted to the fender well with its own heat sink, next pay check, thats my next project, my question is which one do i get?...
There seems to be a cheaper gray one and a more expensive black one, whats the difference? and should i replace the heat sink as well? i know its nothing more than a chunk of aliuminum with fins, but would it make a difference?
Thank you all for your advice so far, anything on this would be helpful as well.

 

You are lucky to find a Motorcraft black one. I am running used and carry a used spare. I have a couple of grey ones that heat up like a grill and I will sell cheap. It costs money to go to school... The original black ICM runs cool. The wiring and dwell control is different. The grey uses the ICM to control dwell, the black uses the front and back side of each notch in the distributor and the PCM controls the dwell.

The heat sink is fine. Use a heat sink compound from Radio Shack between the ICM and the heat sink. There is a tool to separate them but a thin wall deep socket from the Zone worked for me. For testing after you get the new or used ICM before installation drive it until it sputters then just disconnect the ICM and plug in the new one for a little while to see if that fixes it. Just leave it hanging. It does not have to be installed in the sink to work for testing.

Congratulations on doing your distributor right. It and the ICM have about the same life before heat failure. Last will be the PCM.

Next possibility. Mine would lean out and stall when I let off the gas in 108 degrees weather. New Motorcraft oxygen sensor fixed that.

Just for grins, check plug wiring routing for cross firing. Look at your firing order and separate either 7-8 or 6-5 in the wiring loom.

 

ok, along with everything else, i have replaced the ICM, got the black one, seems good for a bit, then low and behold it sputters and dies at a red light, it will restart for a few seconds just enough to get it out of the road and dies again,i wait around an hour or so and it restarts i get another 2 miles and it dies again. this goes on for 4 hours till i finaly get it home.
The last thing it could be is the PCM right?

i was able to get some codes that read off as:
bank 1 lean
bank 2 lean
bank 1 rich
bank 2 rich
missfire on cylider 1
missfire on cylider 2
missfire on cylider 3
missfire on cylider 4
missfire on cylider 5
missfire on cylider 6
missfire on cylider 7
missfire on cylider 8

no codes on the "why".
my battery is the right size, all sensors test to with in specs. no mechanical malfuntions. no oil leaks, a crap load of new parts. all spark plugs gapped properly. every tech i have talked to about it has just scrathes their heads, shrugs and says "I dont know man, I cant figure it out. there is no reason for it to do that"
The last fuel and ignition part that hasn't been replaced recently or in the past year, is the PCM, i've looked at it, there is no sign of physical damage, all connections are clean and free of corrosion.
I have sunk a lot of money into this Bronco, all i want is a good running vehical out of it. im near my limit with it.
Any advice is good advice.

 

this was the first year for a crank trigger isn't it?

 

I guess you cleaned the grounds on the fender by the battery and by where you pull codes?

My intermittent stalling and transmission issue was solved with PCM repair.

Go to Ford GM ECU ECM PCM TCU Lexus Toyota Honda Acura repair used Mitsubishi Print the "Send Unit Form" You can fill it out on your computer before you print it and enclose it with your PCM. They will test it first and repair if needed. When ready to return it they ask for payment.

Release at least half of the fender liner to get the PCM out.

 

is your fuel pump getting hot?

 

X2. Test fuel pressure when this happens. I just replaced my fuel pump again after he hit over 100 degrees. Ran great in the morning but once it heated up it had the same symptoms as yours. Pump was vapor locking due to lower pressure allowing fuel to boil from heat.