wdj, let me know if thats the problem i do suspect it is and coolent temp sensors are cheap and easy to change, ur looking at maybe $20

 

I would agree with the ignition module. my old mans 88 e-350 had a stall problem when it was heated up.

 

your fuel pump may be getting hot and cutting out i belive the is one on the rail and one in the tank or you can have a relay getting hot and cutting out listen for them to click when you turn the key on let us know (FIY) if it is a relay go to a dealer and get them i just went through a problem with after market relays.

 

hopefully you find out what the problem is and let us or me know.. I'm a new member as of tonight to find out why my truck took a dump, JUST LIKE YOURS does EXACTLY the same thing. Tomorrow morning i will find out if it starts again since it's still at the mall. Hopefully it does. ::crossing fingers::

FYI: I've been noticing several things. sometimes my gas gauge doesnt work when its switched on the main tank. it flucuates and moves back and forth tremendously, then on some days is dead on E, when it has a full tank. My reserve tank reads quiet well and the needle works fine but it sometimes flucuates never dies.

 

I have an 88 Ford with 300 I6. You may want to remove and clean the Air Bypass Valve. It is attached to the throttle body. A new one costs about $50, but I would try to clean it before replacing it. I have had to clean mine several times in the 16 years I have owned this truck. I just use Carb cleaner. My truck alway runs better after I've cleaned it. I also have fluctuating gas guages. I trouble shot it to the sending units which happen to be in the tank. They are quite expensive, not to mention a pain to change, so I just fill it all the way and reset my trip meter to keep track of mileage.

 

Benchseat, are you borrowing my truck or something? My fuel guage is also stuck on E. I haven't gotten around to testing that as my priority is the stalling problem...

Anyway, I tested the coolant temperature sensor this weekend. I took it out and hooked up my multimeter and the resistance was pretty close to where I would expect based on the chart located here:

Next step, testing it through a temperature cycle. I took the sensor inside, and bent some wire so that the sensor would hang into a kitchen saucepan. I added enough water to the pan to cover the element, and stuck in a kitchen thermometer so I could watch the temp. As I brought the water to a boil, I used my multimeter to check the resistance at each of the temperatures on that chart between 122 and boiling. On the way up the first time, the resistance was pretty close to where it was supposed to be. On the way back down, it was a little off. But then it got interesting. I heated it up again, and on the second cycle up the resistance was way, way off. I don't have the numbers I recorded, but at one point the sensor almost 100% off - I figured that to be roughly 30-40 degrees too cool. That was enough to convince me to go & buy the $18 sensor and at least give it a try...

Granted, the kitchen thermometer I used was probably a little off (I'm at sea level the water boiled at 200 degrees???) but the thing is that I checked the resistance at the same points each time through the scale. On the first cycle, the thermometer read 176 and my resistance was 3.9 but on the second cycle the thermometer read 176 and my resistance was 6.5. Whether the water was actually 176 or not, the fact is that at one point on the thermometer, I got widely different readings off the sensor.

So I installed the new sensor and gave it a trial run. I drove around for about 20 minutes and stopped at my in-laws for about an hour. The truck fired right up, and I drove it around the block a few times to make sure it wasn't going to strand me at a major intersection. There were no hints of a stall and it got me home just fine. I just might have it figured out. I'm going to do more trial runs each day this week and will post back to let you guys know if this has solved it...

 

Have you chacked your starter? I had a bad siliniod and when it got hot it would not roll over it would only click.

 

No problem with the starter, battery, or charging system. I've never had a problem with it turning over. It just wouldn't fire up for me...

One other question - I think I read somewhere that you're supposed to disconnect the negative cable on the battery after replacing any of the sensors. Is this correct?

 

I am not 100% sure but there are a number of things that is could be. have you checked your autinator? some times you can get a hot wire from your battery and you can touch it to the scilinoid to roll it over or just to spin the fly wheel.

 

Nevermind, I found the page where I had originally read that...

"Once you have installed a new sensor you then re-attach the battery, you disconnected it right? You should have, and not just to protect against arcs, the EEC’s Keep-Alive memory stores the sensor irregularities."

From: http://fordfuelinjection.com/sensors.html

I wasn't sure so I didn't do it last night. I'll go do it at lunch today...

 

radster, there's no problem with the starter, the solenoid, the alternator, or any of that stuff. All of that is fine. The starting system turns the engine over whenever I want it to...

When it dies and won't restart, it's due to something with the fuel delivery. It's either getting too much or not enough...

 

After fixing my fuel valve, I encountered the same problem: truck starts fine, idles fine -- but put it in gear and it stalls.

If I let it warm up for 20 minutes or so, it would drive fine -- but wouldn't restart for hours.

So, I replaced the coolant temperature sensor ($50) -- problem solved!

The truck also idles smoother, runs better, shifts more easily.

 

Woah, that was alot for the sensor, mine was $18 at O'reilly... Unfortunately though, that didn't fix the problem like I thought it did. It just died on me again about 2-3 hours ago...

Next step - fuel pressure tests...

From what I understand, KOEO pressure should be 30-40
KOER should be about the same at idle, but lower with increased RPM's...

Is this correct?

 

did you ever check the fuel cap yet?

 

No, I haven't checked the fuel cap.. can you explain what that might have to do with the problem?.. I honestly don't see any connection..