does any know if a dirty iac muffler will throw a iac code on computer thanks

Yes it has done so in the past.

What engine model?

496 mag ho 2007

If your 496 is a NON DTS model then you will have an IAC muffler. I have seen a few of these throw a code plus can or will make an engine run rough at idle and just off idle if they are very very dirty or injested into the cavity along with dirt. I am talking about the IAC muffler besides the IAC itself. It seems as when the IAC muffler is not in place (missing) on the 496 you will get a surging idle and a louder hissing noise.

thanks for input i finally swapped ecm"s problem moved to the other motor trying to figure out what to do

Check your connections into the problem PCM, check for corrosion issues, next have your PCM checked out by Merc or Dustin Whipple. Next steep if a new PCM is needed you have to fix the cause of what damaged your PCM. Some things are bad grounds, corrosion issues, bad or faulty IAC, bad coil (s), voltage spikes (connection issues)

ended up the bad iac burnt up pcm also had the iac muffler compressed to much and throwing iac code

I havent had mufflers (sponge) in mine for 5+ years and they never threw a code.