another low rpm surge.

[oneno]

Hey everyone have a fairly unique low RPM surge problem , just around 1,700 rpm's it takes off like I had given it a quarter more throttle and cackles loudly. A little background, The truck is an 05' 5.7 Rumble Bee with 52k on the odo. mods are a K&N cai, cats have been removed and was throwing o2 codes so I put plu defowlers and steel wool in them to get rid of the code and no cel in 2,000 miles. About 9 days ago is when it started and is not throwing any codes or cel. it seems to tame down after it warms up. This what I've done so far. Installed new EGR valve, cold ecm reset, cleaned egr tube, inspected and cleaned pcv valve, added some heet for fuel water removal and filled up tank in case it was bad gas. Took it to a Dodge dealership (which I never do)and the mechanic said whoever I bought it from has "Hot rodded" it and did some hot rodding upgrades on the ECM. I wasn't aware of any tunes so I told him to just reflash the ECM and he said that it couldn't be done and I'd have to by a new ECM and should buy 2 new oem cats before they would work on it. Why coudn't he just reflash the ecm with the last standard updated ecm stock tune? I know he didn't want to admit that they could just reflash it for rather than spewing bs, but he said to take it to a high performance shop. He did say the tech had make notes about the idle being 40 degrees above stock and he couldn't clarify what that meant? So I'm going to run another tanks of gas through it and see if it will clear up on it's own or throw a code so I have a start point. I found a used but guaranteed ecm on e-bay at a great price and was thinking about buying it. I'm in need of some good advice and thought this forum would give me a good start. Thanks in advance.