A few tips I learned during my glow plug swap extravaganza today.
1. Get yourself a 1/4" drive 13mm flex socket and make sure you have 6" and 10" 1/4" drive extensions. With this combo I was able to easily remove all valve cover bolts in a matter of minutes. Even the rear ones and the ones on the passenger side next to the HVAC. This was the only special tool that really made a huge difference.
2. The vacuum hose trick works very well to remove the glowplugs from their holes.
3. Lacking a syringe to suck the oil out of the glow plug holes you can blow the oil out with a blowgun. Wear eye protection. Make sure there is no oil around the tops of the glow plugs before removing them.
4. DO NOT drop a glowplug down the pushrod valley. I did this and it took an hour to get the sucker out. You can't leave it down there, its on top of the pushrods and could cause major damage. Take your time. After this mess, I use the vacuum hose trick to reinstall the glows as well so I was sure they were in the right holes.
5. When diagnosing bad glowplugs, make sure your meter is set on regular OHMS. If you have an autoranging multimeter, observe what range it has set itself to. I originally misdiagnosed my glowplugs because of the autoranging reporting 1.2 kOHMs not 1.2 OHMs on a few plugs.
6. I would suggest starting on the drivers side. It is actually a bit harder to get everything to the point where you can pull the valve cover as there is a bit more to remove, but once the valve cover is off there is a lot more room. Its easier to learn where everything goes when you can see it better.
7. Make sure all your glow plug leads are continuous from the switched side of the glow plug relay before buttoning up the valve cover. Clamp one lead of your meter to the stud on the relay and check the wires. It would suck to put new glows in just to have them not work.
8. Just for peace of mind, test the glows once they are removed from the truck. I hooked a pair of jumper cables to the passenger side battery and tested them for a glow. Clamp the threaded end of the glowplug with one cable and touch the other cable to the stud where the wire connects. You will know right away if the plug is good or bad. There will be a little spark as you clip the leads to it and the oil on the tip will start smoking as the oil burns off and the tip will glow within a few seconds. Once I found 3 of 4 plugs on the drivers side did not glow, I was pretty sure I had found my cold start issue.