OK – thought I might be able to trouble shoot this by reading all the other threads I could find on it, but I am not sure my problem fits exactly with the others I've looked at. I recently purchased a 2002 EGlide EFI (FLHTCI). The bike has V&H oval slip-ons, K&N breather and stage 1 download. It has 14K on it and was running near normal when I bought it a few weeks ago. I had the local HD dealer perform a 15K service and they thought everything looked good/ran fine. It had decel popping that prior owner told me about – he thought the fuel mapping was off (has RevTech DFO), but dealership told him they had “optimized” it. However, since I bought it the engine is not running well at low speeds. It basically runs fine under mild/strong acceleration or at full highway speed and seems to idle normally when the bike is started. However, when cruising along about 25-30 mph (in either 2nd or 3rd gear) it is always misfiring and sputtering pretty bad now (had a little hint originally and definitely getting worse now). After coming to a stop, the idle is a bit rough and sometimes the engine acts like it wants to cut out for a few seconds after which it seems to idle OK. The popping/backfire also continues about the same on decel as when I got it. The symptoms appear to be about the same whether the bike is cold or warmed up. I was thinking it might be bad gas (last owner did not ride it last year). I have put 3 tanks of 93 octane through it and no change (and no difference between full or near empty full tank). I also consulted with RevTech and tried adjusting the DFO pot settings which seemed to be way off from what they should be for my set up, but I can’t notice much change across fairly large adjustments. RevTech thought it was likely an intake leak, but before I start making a mess with WD40 to check it out, wanted to get some feedback. It seems like an intake leak would make the bike run rough at idle too. I have pulled the diagnostic code from the data link and on the tables I pulled off this forum I am getting a 34 which is listed either as loss of idle speed/air control and/or starter output high. I had squirted a little carb cleaner into the air intake which caused a quick loss in rpm so maybe that caused the trouble code – not sure. Any suggestions on what problem I should be going after or how to verify?