This is my first winter with this truck (1999 F250 7.3 Diesel), and as the temp drops outside, it's getting harder and harder to start this thing. Its otherwise running perfect. I love it.
It fires a little later than in warm weather and when it catches it seems to be only running on a cylinder or two. RPM bouncing up and down to almost zero each time. Truck lurches over and over until it finally smoothes out. I tried doing two glow-plug warm up sequences before turning it over. Seems to help a bit, but i'm not sure if I'm damaging anything in there. Any ideas? I'm planning to install a block heater this weekend, but it seems silly to plug in a vehicle when the temp is still above freezing.

 

Sounds like you have some glow plugs on the fritz, or even the relay. It should not have a problem starting or running smooth above freezing or even quite a bit colder. A properly running system should not make much white smoke or buck and spurt.

Here is a good tip for replacing the Relay to a heavier version:

Welcome to guzzle's Modifications Web Page

Also you may want to start adding the White version of Diesel Kleen additive that has anti-gelling properties.

 

Welcome to FTE. First, I'd like to point out we have a section here dedicated to the 7.3 motor, so if you scroll a bit further down the main forum listing page you'll find the 99-03 7.3 section. You'll get plenty of more responses there since everyone has the same engine you have.

Now on to your question. You need to know that the wait to start (WTS) light on the dash is NOT connected to your glow plugs in any way. It's just a reminder provided by the computer. You're glow plugs will come on for 0 - 120 seconds depending on temperatures and things. Cycling the key like you're doing will not hurt anything. You can also just leave the key in the on position for several seconds after the light goes out since the glow plugs will likely stay on the same amount of time as cycling the key again.

Since you're new to the motor, we'll start with the easy stuff first. One morning grab a multi-meter and before you turn the truck on, check the voltage on the 2 large posts on your GPR (glow plug relay) One should read 12 volts and the other will be dead. Next, turn the key to the "ON" position (not start) and quickly check the voltage on the "dead" post of the GPR. When the key is first turned on, the relay should be energized and send power through the other post and then on to your glow plugs.

You'll notice there are 2 similar relays next to each other in that picture. The one toward the rear of the truck is the GPR. If you have an early 99 model truck, you'll only have one of these relays which will be the GPR. That is normal and nothing to worry about.
If you don't see any power at the other big post, hold a screwdriver across the 2 big posts on the relay for about 45 seconds (shorting them together) and see how your truck starts then.

If that doesn't work, come back and we'll tell you how to check your glow plugs with an ohm meter.

 

Thank you for the responses! I've been tied up with my wife's Subaru for the past couple days. New CV joints. How come everything else has to work perfectly before I can spend time on my truck?! :-)
I'm going to try your procedure this weekend, Chris. Thanks again.
Yes, next time I'll post in the proper section. I hadn't scrolled down far enough to see it. TONS of info here! Once I've tried your glow plug voltage test, I'll post over there, and copy your message there too.