A/F ratio off?

Just an update on the situation up until now.

I just started it up to take it for a spin, it started up fine, I was just letting it warm up a tad because its pretty cold out, no backfiring or running rougher than usual. As I started driving I noticed it backfired once when I hit the gas, so I stopped and checked everything (never backfired before), it was idling and running great (still a bit rich A/F though).

It seemed like it was running funny, kinda surging and stumbling occasionally, so I got off the highway and pulled into a parking lot, it was idling just fine no noises or anything. So I pulled out of the parking lot and It was running like absolute CRAP!! didn't feel like it had any power and stumbling a whole bunch, felt like it wasn't getting fuel (but why would it backfire if it wasn't getting fuel??), also the wideband read 10:1 for a while. So once again I pulled over, and this time it was idling funny, so I stopped and looked things over again, I though maybe the timing changed, but everything was tight. Everything seemed fine to limp it home, so I started it up and it was still running like crap! didn't want to idle, and surged like crazy as before. On the way home it started to run like normal all of a sudden, no surging or power loss. It seemed like the running like crap was intermittent, as I got home it was running fine again. The choke wasn't stuck as mentioned before either.

The only thing that I changed was getting gas, before I got gas it was running like a champ, so I am thinking that I could have gotten a bad batch of fuel or something. Maybe some water got in the tank? I have put at least 1500 miles on this car with the new setup and had no issues at all. Don't think its a vaccum leak either, but who really knows...