Miss at steady low power?

Hey guys have had a miss in all gears at a steady low throtle . Have 500 miles on 03 1800s. It has done this since new. Runs out great in all other respects. Have hard krome 2-1 sideburner exhaust. Put those on about 250 mi. , but it did it even with the stock exhaust. I haven't done the de-smog and I haven't done the ground fix. I have been having to much fun riding. But before iI do those two things does anyone have any Ideas other than those. I suspect a possoble intake leak somewhere the way it acts. Any thoughts on where I might start to look for an intake leak ??? Or maybe there are some othere Ideas out there that might nail it exactly. Just dont feel light tearing the bike all apart right away .
Thanks for any help.
Come on Spike I know you know what it is. LOL