My blazer through up a code, I think it was p0013 which was Airbank 1 or 2, and since then I have reset it, came back on, reset it again, came back on, rest it once more and it hasn't come on since (this was over the summer)

Is this a big deal?

 

That code has to do with camshaft position actuator circuits. These 4.3s don't have any sort of camshaft actuators on them, as far as I have ever seen. Secondary Air Injection circuit problems are usually in the lower P04xx area. The AIR systems are for emissions only, and a bad AIR system shouldn't pose any performance problems, but if your state has emissions testing, you will never pass with a SES light on. If you throw another SES light, you will have to get the code from a scanner, which they have cheap ones at your local parts store. From there, it is easier to narrow down the problem.