Jboom,
There has been quite a bit of discussion on this issue, and many of us have found that ramping-up the temp slower solves it. In my #1, I never experienced this at all. When I was testing the digital model 2, I had it happen. Check out this post, with some videos of it:
http://smokinitforums.com/index.php?topic=1345.0I now set my temp to 130 for the first 1/2 hour, then move up to my desired cook temp. This lets the wood start smoking (usually at about 12 minutes), then "rest" with the element off for a bit before the blast of heat hits it again. Since I've used this method, I haven't had any more combustion. You did right by not opening the door. Not good to introduce a big blast of fuel to the fire! The "belch" is like a back draft effect, and is actually the fire being blown out.
In the models 2 and 3, the heating element is a lot bigger than the #1, and really puts a lot of heat to the wood quickly. Give it a try next time.
Another tip - don't bother with trying to check the temp in an empty smoker. They're all over the page, as there is nothing in there to absorb and hold the heat. It will only frustrate you.