Troubling change to cold start-glow plugs?

[buddy357]

My 03 Excursion has been a little slow starting when its cold lately, it's pretty much time for new batteries. I got off duty tuesday morning(40 degrees) and it started as it normally does leaving the ship. Wait to start goes out and then it drags slowly turning over like there is a big load on the electrical system (glow plugs I think) then catches.

On the way to my class (maybe 2 miles) I came across one of my guys having car trouble and stopped. As soon as we got his tire on I cranked the truck and it turned over pretty fast like there was no load on the battery. It also didn't crank until I went through this process 4 or 5 times (approximately 10 seconds each time) and finally caught. When i got to school and turned it off it warm started fine.

Lunch time was the same thing, very fast engine turning over but slow to start. I skipped lunch to take the Excursion home and get the jeep and the EX started fine warm. I got home today (70 degrees) and on a lark tried the EX and it started right up. It's almost like theres no draw for the glow plugs or something.

Anyone have any ideas where I should start this one? I dont have the auto enginuity yet. I was waiting til I decided whether I was keeping this or the jeep. Guess I may have to get it after all.

I forgot to add that when it finally started when it was cold I had white smoke rolling out for the first minute or two then none.