Stalling on the way home from work!

[fivespeed3.0]

I have a 2000 Ranger 4X4, 5 speed with a 3.0 flex fuel with about 140K miles. I'm having a little problem only when it is cold. It sometimes just dies after an acceleration and during coasting to the stoplight before it is fully warmed up (it always happens in the same place???). Sometimes it is hard to restart, but it restarts. It happened again today, but I was able to restart easily while coasting by letting out the clutch. I did notice some hesitation when I was accelerating prior to these events. Again, it only happens when it is cold. I am running E85, but have been for a long time, but have not been loyal to one station. Could it be fuel related? Could it be the fuel pump (original)? Could it be something else?
Any help will be greatly appreciated!

Thanks

 

[Big Jim M]

It could be the temp sender for the computer isn't telling the computer the complete truth..
Big JIm

 

[fivespeed3.0]

Thanks for the reply!

Is that the IAT?

 

[Big Jim M]

NOPE! The IAT is the Incoming Air Sensor.. That ain't it.
You have TWO coolant sensors located near the Thermostat housing. One is for the gauge on the dash. The other is sort of a SWITCH inside. It remains closed or open (I have never tested one to see which) until a certain temperature is reached. At that time it opens (or closes) to change the signal that goes to the computer.
When the computer gets this signal it switches from a rich mixture with retarded timing to a LEAN mixture with advanced timing.
If the thing is hung up and tells the engine a lie then you will get poor running either when cold or when warm..
Big JIm

 

[Big Jim M]

By The Way... The test is to unplug one of them and if the gauge doesn't work that is the WRONG ONE!
Big JIm

 

[fivespeed3.0]

Thanks again for the reply. Would cleaning the switch help or is it something that just needs replacing?

 

[Big Jim M]

The problrm, if the switch is bad, is internal and not repairable. They are real cheap and easily found.
Big JIm

 

[fivespeed3.0]

Thanks for your help Jim, I'll give it a try.

Also, just FYI, I looked it up in my Haynes manual, and it said the two sensors are easily differentiated. The one going to the gauge, usually called a sending unit, has only one wire going to it, while the one going to the computer, usually called a sensor, has either two or three wires going to it.

Thanks again for your help, and I'll let you know how it goes.

 

[fivespeed3.0]

I replaced it. The old one looked pretty gunked up. The real test comes next week on the way home from work. I took it for a test drive last night just after replacing it, and it seemed to run a bit smoother cold, but we'll see.

 

[fivespeed3.0]

So far, so good. No stalling yet this week. Thanks Jim!!