I ride a fuel injected 2006 Springer softtail - that has had a fair amount of cosmetic customization done to it. Other than lengthening some wiring, the electrical, motor and drivetrain remain completely stock. It has just under 12K miles on it since the customization and had been running fine up until the past 2 months. In fact, I rode it from Phoenix to Sturgis and back this past August. No issues to speak of over the 3K miles of the trip. Since most of the posts on this site seem to come from people with a lot of knowledge on the topic, I wanted to get your opinions on what possibly could be causing my issue. I know it’s a bit longwinded, but I wanted to make sure to give anyone reading this enough information so they could make educated guesses at the issue. Issue/Symptoms: While going down the road, I have an intermittent hesitation or miss. When I experience the hesitation, it also seems that it is huffing (best way I can describe it) through the intake because the air filter is getting black. It’ll be black within 200 miles of a recharge. I also have a lot of popping in the pipes under deceleration and occasionally even while travelling down the road. It also seems that the hesitation happens more at low to mid range RPMs and not as much at higher RPM ranges. Problem is not noticeable to the ear when the clutch is engaged and/or the motor is just idling. I should also mention that the initial start in the morning, the engine starts, and races up in RPMs right away then hesitates and dies unless I give it a twist of the throttle right away after starting. If it does die, I'll restart it immediately and it will stay running and seems to warm up normally after that. Not sure if that helps at all but wanted to throw out everything I can think of. Customization: Replaced the stock buttons with PM Contours - spliced in their wires to the HD wiring harness. The PM buttons leads are a different gauge wire (smaller) than the stock wires. Also, the leads are approximately 36" and I used all of that so I could run them internal in the handlebars. I did put a layer of heat shrink tubing over each pair of leads, then another over the 3 sets of wires before running them through the handlebars. Running SuperTrapp Crossover Shotguns pipes. - I tape wrapped them about 6 months ago in hopes of getting a bit better performance. Running the Stage 1 air cleaner with a K&N filter. HD EFI race tuner installed. Not sure which mappings if any were applied? Investigation: In starting my investigation, I thought it was maybe a break or short in the ignition wire from the buttons to the ECM. Since changing the buttons was one of the things I did during customization, I thought that this might be a good place to start. I did find a pinched wire, right where the wire bundle pass between the frame and the fork stop so I spliced the break out. I didn't find any other issues for the turn signal or the kill switch wires. I didn't use the exact same size wire when doing the splice but used something close. It's was only a 1" splice piece. The splice piece was 20 or 22 gauge wire. Result: No change. The second thing I checked after reading this forum was the gas line between the fuel pump and the petcock. Found that the clamp may have been a bit too tight, or the hose was too close to the end right by the fuel pump connection so there was a pin hole sized leak. I back it off about a 1/16" and tightened it appropriately. Doubled checked it for leaks before stuffing it back in the tank. Result: A little better. Fuel line maintains fuel and pressure better even after shutting off the bike but I am still feeling the hesitation. Another thing that was changed recently was the spark plugs. I changed them just prior to the Sturgis run. I double checked that they were properly gapped before the install and after about 100 miles of usage. Result: No change. Finally, after reading a lot of information on your forum, I checked the ECU codes. P - None S -b1021, b1022 - Not surprising since I don't run front turn signals. SP – b1004, b1005 – These also make sense since I got rid of the gas float and gas gauge. T - None A friend of mine, that's done a far bit of motor work in his past, mentioned that he thinks the bike is running lean (causes the popping on decel), and that I may have a fuel injector going bad??? I can accept that, but if that would be the case, wouldn't the ECU be calling attention to those items? Additionally, if I had an intermittent ground with the wiring, wouldn't the computer call attention to this as well?