What you are describing is not surge.Well i just took the whole chip out of the truck to make this trip this morning. Still there. It seems to do it while im just driving. no acceleration or anything. just cruising. It will also do it when i am slowing down as well. One time while it happened i put the thing in Neutral to see if i could get the turbo to slow down and it was still there for bout 10 seconds while i coasted then it just quit. If surge isnt the prob i hate to spend $400 bucks on a housing i dont need i guess. Just confusing as hell.