Marathon while Sick?

I'm scheduled to run my second full marathon this Sunday. Up until this week, training went well, and I felt on course for a great shot at a big PR (shooting for a 4:10). I've come down with the only cold I've had this guessed it...this week. I'm on day 4 of the cold and haven't run at all in the last 3 days. The marathon is 3 days from today. I'm pretty sure it's just your garden variety cold, but am now in the hacking up a lung phase. I'm 46 years old, type 1 for 20 years, and yes, a little scared of messing myself up in a bigger way if I don't feel a lot closer to 100% than I do right now.

Any thoughts or experiences you are willing to share on making that decision would be appreciated. Oh, and this is my 5th year running this race, and will complete a finisher medal series that I really want. If I drop to the half, I need to decide like yesterday. Ugh!

If you were having a good taper week you'd feel "off" as well for a few days. See you feel in a couple days. Lots of liquids. Critical to make sure BGs aren't out of whack the last couple days prior to the race. Good luck!

Thanks IMVic! I went to the doc just to make sure I'm right on the "just a cold" part, and looks like I'm good to go. Yep, working to keep the BG's in line.