geordieboy

I have a 1984 with what I think is the V8 4X4 5.0 automatic.
The engine cranks up fine when cold. It does run a little rough and idle low, but will run. Once the engine is warm, i have had 2 experiences.
1) engine runs really rough and stalls if you do not keep on the gas. This has been when air temps have been pretty cold out.
2) Engine runs pretty smooth, but when you stop the engine it will not restart until it cools down. The cranking sounds very strong, just will not start. This was the case today when the air temp is around 55 degrees

I checked that the choke flap was fully open once warm (vertical)

One thing I noticed was a little liquid sitting in the reservior in the air cleaner housing that connects to the oil filler cap. It was smoking a bit also.

I do think I am leaking some antifreeze from somewhere if that is relevant...

Does anyone have any suggestions to this newbie to the F-150 world!

SmokeStack

Start with the coil its cheaper.
then the Distributor

Kickprivate

How long did you try to start it while it was warm? You say it won't start when it warm, did you drive it for 10 miles then try to start it again? Did you just sit in your drive way, warm it up and turn it off?

geordieboy

I have done both.

After driving just a few miles it would not restart.

Sitting in the driveway warming it up, although not running it hard - it did start.

Have not tried letting it sit in the driveway for a long time running then trying to restart.

Kickprivate

How sure are you the engine is warm? If you are going by the choke system to tell you that the engine is warm you may find out that the choke may be out of spec and some adjustment may be needed.

When it's cold out, the Butterfly valve should be all the way closed after tapping the throttle, this enabling the fast idle cam to engage and the choke pull off should be the only thing holding it open after the vehicle starts and is running by pulling a vacuum on the choke pull off. My 84 Emissions sticker states that the fast idle cam should be set to 1900rpms or so for the first setting on the fast idle cam.

Driving a few miles doesn't mean the engine is warm if the temperature is 17F with a wind chill of 10F so confusion could be created by assuming the engine is warm, when its cold. In-proper choke adjustment can be a culprit of many engine wont start problems when the engine is cold; but so can fuel delivery and electrical problems. However it may be easier to research and understand how the choke system works and adjust it based on that then to spend 200-500 dollars fixing a problem, when you are not sure there is a problem with that particular side of the system.

Sitting in your truck on a 20-35F degree morning, watch it warm up. Mostly keep an eye on the temperature gauge and notice how every 5-6 minutes the T-stat opens dumping cold antifreeze into the engine, the heater in your truck blows cold air and the engine can even begin to slightly stumble a little. This will happen every 5-6 minutes about 2-6 times depending on the outside temperature.

So this is what I suggest to you, thoroughly warm up your truck when it at its coldest and see if you still have a problem. The best way to see if you really have a problem with a truck not starting warm is to really warm it up, drive it 20 miles or sit in it for 30 minutes. Then make from what you learned and now know, this can point you in the direction of your problem.

I surely hope this helps you in some way, I am as experienced as the problems i have fixed on my truck and this is something i have dealt with before on mine. In the end for me it was a Fuel/Choke problem.

Kickprivate