OK I know this topic is flooded all over the net. So this is my attempt to get a solid correct answer besides swapping parts.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
Truck runs great if I get it started.<o></o>
Here are symptoms.<o></o>

• Extremely hard to start when engine is cold<o></o>
• It will start fairly quick if plugged in all night<o></o>
• After running there is no issues with starting unless sits over night<o></o>
• Batteries good and engine cranks fast<o></o>

Tests and parts I have replaced<o></o>

• Replaced GPM (Glow Plug Module) I do not have the relay as most seem to have on their engines. I did replace this unit for $180.<o></o>
• Replaced Glow plugs all 8 this morning. Since they where cheap enough it did not hurt the wallet. $11 each<o></o>
• Replaced crank position sensor. Bought at Ford dealer $32. Tach moves when engine is cranking<o></o>
• Checked the HPOR and it has oil about 1/2" from top.<o></o>

Now what is left to check besides doing a buzz test to rule out injectors?<o></o>
Also if truck runs fine and does not run rough could injectors still be bad? <o></o>
If anyone lives near Manassas,Va and has Autoenginuity scan tool software or another diagnostic tool to perform test that would be great.<o></o>
I appreciate any good feedback.<o></o>
<o></o>

 

Excursions do not have glow plug relays like the Super Dutys. We have Glow Plug Modules like the 6.0L engines have on them.
When you say it runs fine once it starts, how well does it start? Does it take forever with it cranking over to start? It may be losing prime in the HPOP or has a leaking oil line. You say it starts fine when plugged in, that leads me to think GPM or glow plugs(You just changed them and may have solved your problem) . Does it smoke when it starts if it is not plugged in?
I agree an injector buzz would be helpful as I just had #4 come unplugged last week. Now I have the wedges and don't have to worry about being stranded somewhere now due to the UVCH coming loose. Does it rattle really loud like an extremely cold start??
A little more info and the guys here will be all over it!

 

I don't know if you've found a solution but I had the same issue with my 2000. It took 3 shops to find it but it turned out to be a IPR valve. Apparently it is very hard to diagnose.

Good luck.

 

Actually I pulled every fuse and relay and put them back in and all works great. Hit 20 degrees in Va and starts right up.