^ my car backfired at one point last winter (long story short, the car doesn't start at temps below 40 degrees) and actually broke the MAF sensor. Two actually as I guess I didn't learn the first time. If you cleaned it though, I'm sure you would have noticed if it was there or not. When I compared mine to a pic on the internet, the entire thing was completely gone, haha...
Is your intake boot in good shape?
Miss-Fire code has to be just that though, right? I wouldn't think a bad intake boot or dirty EGR would cause a miss-fire code, could you have possibly purchased a bad coil pack? I'd suggest pull the plugs and look them over really well, and work your way up from there...
Let us know what you find out!
Thanks, I've got some weird popping coming from the front every now and then, but that noise went away (in the back) when I pulled that sway and those links. hmmmmmm