I am posting this for a buddy of mine.
He has an 03HO 2500HD with auto. Only bombing done is a AFE stage 2 intake and an edge EZ. After the EZ install the cruise control is screwing up. If you set it to say 60 mph it will drop back to 56 then throttle back to 60 then drop again, so on and so forth. If you remove the EZ the problem goes away. The shop he purchased it from called Edge and they say they have never heard of such problems. Has anyone else experienced this? Is there a flash that will resolve the issue? Is it a faulty programer? Your input------

 

Pretty common problem. I would search "Cruise Surge" I believe there is a way to fix (or reduce) it by inserting an aresol spray can tube (WD40) in the vaccum line somewhere.

 

My 02 standard tranny truck intermittently has the same thing occur. Mine started with installation of my EZ. I have found that if you will turn cruise off then back on and re-set speed that it usually works fine.....

I don't worry too much about it though, cause down here in Houston, the ID10T in front of you invariably can't drive the speed limit or likes to ride his brakes.....

Gary