'96 exploder dies randomly

[Explorern00b]

I have a 4x4 '96, V6. While under a load, in hot weather, it will randomly die, acting as if it's starved for fuel. About one in five times, I could keep it running by playing with the throttle, but most times it just dies out after slowly (~5-10 seconds) winding down. After about 10 seconds, I can start it up, runs normally, and works great, until it decides to die again. Sometimes this happens as soon as a minute after the last episode, others it will run for 5 minutes. This problem happened while pulling a U-haul trailer most recently. Last time it happened, we were driving with just the truck loaded with suitcases and such. Both times, the outside temps were around 95-100 degrees, but the temp gauge reads normally. This problem won't repeat itself without a load, or after sitting for more than an hour. I have had it at the Ford garage, and at a Firestone shop, neither had a clue.
Fuel filters, plugs, wires, coils, idle air controller all replaced, O2 sensors not testing bad, no fuel leaks, and the truck isn't offroaded. I can fix most anything you throw at me, provided I have an idea what I'm looking for, but this has me baffled!!

Please let me know your ideas,
Thanks

 

[b33p3rmcg]

Understand I'm not even close to being a mechanic but I noticed you haven't mentioned fuel pump. I know there are posts in here about testing fuel pressure. If it were me I'd check that out.

 

[Explorern00b]

Have

done that, except when the problem is occurring. The unfortunate thing is that it stops doing it after parked, when it happened last year, we had to wait for a tow (we were in Chicago during rush hour on the expressway) and by the time it got to the garage it wasn't doing it anymore. When I got it home this last time, it smoothed out, and it tested fine, around 60-ish psi. I thought about this too, but I don't want to throw a fuel pump at it when they cost so much. Plus the truck is from the rust belt, so I'll have to replace the straps and hardware if I pull the tank, if it's all for nothing, it's an expensive maybe.
Thanks for the suggestion, though.

Any more?

 

[Mr. Logger]

Is it spitting any codes at you? I had this happen on my Mounty, and eventually it had codes about the MAF sensor. Just so happened that the MAF sensor I just bought was f'ed up. Took the stock one, put it in the new housing, and it runs fine now.

 

[Explorern00b]

codes

It's always had a code for multiple random misfire, even the Ford dealer couldn't figure out what was causing it. It runs fine normally. I'll give the MAF a try, easier and I can come across one cheaper than a fuel tank.
Thanks!

Just in case, please keep the suggestions coming, and I'll let you all know what works, if I ever know. Like I said, it's soooo random.

 

[budwich]

OK.... so you say "after 10 seconds, it starts back up".... what happens when you try to immediately start it? Does the Check Engine light go out during the crank? My guess is the fuel regulator has a problem... check it for gas in the vacuum side of things.

 

[Explorern00b]

If

I remember correctly, the check engine light goes out, but I can't say for sure. If I try to start it up immediately after it dies, it will crank and crank, no fire at all. Is there a way for me to check the regulator?

Like I say, when it dies, it dies really strangely, to me. You can watch the RPMs drop slowly, if you hit the accelerator, they drop faster, but there is almost no coming back once it starts dying.

Thanks again, I'm going to look into the regulator, as well.
As before, I'm not averse to other suggestions, if you have one, there's a chance I haven't thought of it, so please post it.

Thanks for the replies, coming on here to ask was a better idea than I thought

 

[budwich]

lastly, to try reproduce your problem and maybe narrow down your "hunt", take a heat gun (hair dryer) and blow on places like the regulator, pcm module, sensors, etc while your truck is idling and see if a certain place causes it to die.

 

[Cobraguy]

Don't count out a fuel filter. Just for grins and giggles, I would pull your filter and check it to see if it's still good.

Here is what I would do. Go get a fuel pressure gauge and attach it to the rail. Run the line up out of the hood some way. I've used small, copper line in the past so it would fit through the rear seal area of the hood. DO NOT use plastic line. Tape the gauge to the windshield in an out of the way place. Now drive the car and watch the fuel pressure when your problem pops up. By the way, you could also purchase an electric fuel pressure gauge if your more comfortable with that and place the gauge in the cab. They are expensive though. But I think budwich is on to something with a fuel problem.

 

[96eb96]

It's always had a code for multiple random misfire, even the Ford dealer couldn't figure out what was causing it. It runs fine normally. I'll give the MAF a try, easier and I can come across one cheaper than a fuel tank.
Thanks!

Just in case, please keep the suggestions coming, and I'll let you all know what works, if I ever know. Like I said, it's soooo random.

crank position sensor or wiring sounds flaky. When you crank and it don't extingush the engine light (usually this is an indication but not 100%) the sensor is bad. Check the toothed wheel that is on the crankshaft and the sensor gap, wiring etc.

The only device that reports misfires is the crank pos sensor. Its also responsible for starting and running correctly. If its random and there are no other symptoms here is a big clue. They definately fail and are hard to detect without equipment(labscope) and electronics knowledge. I dont think its an expensive part either.

 

[Explorern00b]

Excellent

advice, you guys gave me alot of info to work with. Saturday, I will have time to check these, and I'll let you know what I find. Maybe in the process I can find something to do a writeup about, who knows?
Thanks again, and as before, if there's any other suggestions, feel free, I check every day.

 

[Flux]

Iac

I was having the same problem of not idling until it was warm. I just replaced the IAC with a new one for 45.00 at Autozone and it completely fixed my problem. Was worth it for me to try it.