03 6.0 black smoke intermittely and idles fine
 

I have an 03 F350 with a 6.0 in it. It starts and runs fine but just started today it will loose power and just bellow black smoke out. If you hold it to the floor it will clear out and run fine and few mins later same thing. It starts and idles fine. I was thinking egr sticking. I hooked up my scanner and no codes and everything looks good. Any ideas?