EFI Engine Surge/RPM flux Problem: At steady throttle when driven approximately 25 MPH in second gear, for about 1.5 miles, RPM drops and returns to original value. It appears the engine is leaning out and when you increase the throttle, RPM’s increase. If you remain at the same MPH, the drop in RPM increases to the point of the bike bucking violently. At this point, the only way to stop it is to slip the clutch increasing RPM’s. It also happens in First gear, just at a lower MPH. The bike remains un-drivable until you start is up when the engine cools down (First start of the day). Driving the bike at higher RPM’s, at a steady RPM, there is still a RPM flux, but it is drivable. Bike: 2006 Dyna FXDI. 100% Stock. 35K Miles. Driven in all weather, all year round. North East Florida area. History: Three times the engine quit on me while driving, just like the engine kill switch was on (MPH went to Zero, but everything else worked). After cycling the kill switch, the engine starts. The bike was in storage for Five, Two, Three, then Two months, driven only 10 miles between each period. I put fuel stabilizer in the tank during this period. The bike has always had a slight engine RPM flux at low RPM steady throttle. About 500 miles after my final storage period, the RPM flux started to get worse. When you increased the throttle it went back to normal. Varying the throttle there is no RPM flux. Within the next 500 miles it was not drivable (above issue). I replaced the spark plugs and it returned to normal. The plugs looked fine for an EFI bike. After the next 500 miles, the RPM flux returned to where it is today. Things done since this problem appeared: Replaced the battery (was not taking a full charge), air filter, fuel filter, spark plugs,(X2), drained the fuel and replaced with new fuel, tried Screaming Eagle spark plug wires (no change and the resistance was the same and within HD limits), measured the resistance from the ECU to respective plugs for all EFI wires (with the exception of the idle control solenoid) with no faults found, coil resistance checks good, used WD40 and Propane around the intake manifold (no change in RPM). The local HD dealer, checked the fuel pressure and hooked up a scanner and found no faults. I also disconnected both O2 sensors and it ran the same (no codes or check engine light). I removed the engine temperature sensor from the engine and plugged it back in, thinking the computer would not register the engine temperature. I then got injector high codes for both injectors. There has never been a check engine during engine operations with the exception of start up which is normal and no codes found with the exception of the previous. Thoughts: Engine is running lean at low engine loads and low RPM's. Possibly O2 sensors. Ever since this has taken place, I have used 10% ethanol 93 octane fuel (Only fuel available in Florida).