When it's cold (below 40 degrees) I plug my truck in. In the mornings it starts and runs no problem. Problem is when I get to work and it sits for 8 or so hours and the temp doesn't rise or it gets colder thru the day it will start and run for bout 10 seconds then rev up and die. It would take a few mins of cranking to get it started again but it would start and run fine. Now its getting to where the 2nd time it starts it runs for bout 20 seconds and dies. I run the batteries down tryin to start it and have to jump it with 2 trucks and it still takes about 30 mins hooked up to both trucks before it will start. Once it starts and runs a bit I'm good all the rest of the day. This past weekend we went camping and I didn't think to plug it up and next morning started it (temp was bout 35ish) and ran bout 10 seconds died. Started a second time ran bout 39 seconds and died. Tried the rest of the day off and on to crank it to no avail. Had a buddy come out and we hooked it to his truck and my wife's truck and tried about an hour. No luck. Plugged it in and next morning (temp was bout 45) after a couple attempts it started ran 10 seconds and died. Cranked it again started and ran just fine the rest of the day

How long does it take to hit the first time? If it is starting right up, then dying, look for a fuel supply/air intrusion issue. If that first try takes a bit before it hits, the look for possible bad glow plugs. Have you tried to hold the throttle wide open until it catches and runs? I realize that isn't the ideal method, but it will tell you if there is a fuel/air problem, or if it is glow plugs. If it is glow plugs it'll usually keep running after it coughs and spits a little. If it's air, it will die no matter what you do, until you replace the air with fuel.

Keep an extension cord in the truck, and plug it in at work. I'd also add a trickle charger (Battery Tender brand) for each battery, and wire up the block heater plug to power them, too.

As Oldrebuiltdodge posted, you've got problems with either fuel, electrical or both. If both are in A-1 shape there's no way you need to plug in a block heater at 25° to 40°. If your glow plugs and everything else is OK it should fire right up and keep idling (with a lot of smoke for the first few minutes.)

I was having this problem with one of mine, installed a check value inline before the mechanical fuel pump starts like it should now.

Thank y'all. Since this post I was able to find a parking spot at work where I can run an extension cord and plug it in. Since I've been doing this I have had no issues with it dying after it starts. Any ideas as to why I don't have issues when its plugged in?

This is a good short-term remedy but you are doing the right thing by investigating the cause since it will get worse.

Your glow plugs are weak. Use an ohm meter, after it sits overnight check tip of the glow plug to ground. It should read somewhere around .2 ohms. If they read higher they are shutting down too soon. If they read lower, they might be shorted out. At that point you can pull them out and test them with voltage, and watch to see if they glow red all of the way to the tip. If they don't, toss them, and replace with Motorcraft ZD9 glow plugs

Thank you. Being that I have no idea if or when the glow plugs have been replaced and even tjo theres only 155,000 miles on the truck I'm going to replace them and see where that goes. I'll keep ya posted

^^^THIS^^^

But it still sounds like more than just a GP issue if it won't start at 40*.

I've had GPs not let it start @80*. It just depends on how strong the engine is. Maybe I should say how worn the engine is.

Not doubting you but why does it run for 20 seconds and then die?

The only other thing it can be is fuel, he eliminated that by plugging it in and it starts and continues to run. If it was fuel, it wouldn't do that. If you start it on weak, but still operational glow plugs, and just let it idle, it will do just what he is describing (which is why I told him to lay on the throttle to try to start it). Hit then die because the cylinders are still too cold for the heat of compression to carry on. I usually get these things when they are where no lone else wants them. A couple of the old girls did just what he described. Glow plugs cured the trouble, and they would still start in 0* weather too without the block heater. With the new glow plugs of course.

New glow plugs installed just waiting for it to get cold again. New issue. For the last couple of weeks it has started to rough idle. I noticed fuel leaking from on top of the filter housing. Investigated and determined the o-ring on the fuel heater was bad. So I figured that's where air was getting in. Where can I get this o-ring. None of the parts stores here have one that will work even the Ford dealer doesn't have it (I can get a new heater with the o-ring for only $288). Every o-ring I have tried is to fat and wont let the heater set right in the filter housing or is not wide enough. I went ahead and put it back together with a regular o-ring just to see if it would work and it's worse now than before. I cant make it around the block without it dying when I come to a stop.

That's a little bit too high. I admit it was about 6-8 years ago but my "friendly" Ford dealer charged me about $130 for the heater in the white/blue Ford box. Inside was the heater in a plastic IH (International Harvester/Navistar) bag with IH part number 1816602C91. I later phoned an IH dealership and asked price and availability, only $60. Ford part # is F2TZ-9J294-A.