I traded my '05 Electra Glide Classic for an new '08 Ultra Classic. The '05 had a SE Air Filter and a set of generic glass packed mufflers and I tuned with a SERT and it ran great, got 45-50 MPG in back road cruising, good power, excellent throttle response. Likewise I installed the SE Air Filter and a set of SE (catalyst) and tuned the new '08 with a SE Pro Super Tuner. Again, it ran good, gas mileage is not as good as the old '05, but it was OK. One day while cruising the North Georgia mountains I noticed a problem with the throttle response. After backing off the throttle going downhill and rolling back on (as smoothly as possible) the power didn't come back on smoothly. It was like a lean surge as the power would come back on. At times the power comes back on sharply enough to clunk the driveline. I hadn't noticed this in six months of riding, but suddenly it was there. I felt like it was a hardware related problem. After I started getting some codes (P1511 and P2102) I took it to the dealer. They gave me standard response number 1 - "they all do that." The second trip I got the - "we didn't find a problem" response. I took it to another dealer who acknowledged that there were codes and it did surge, but they didn't know what was wrong with it. They suggested that I "ride it till it breaks and bring it back." Yeah, right! I put the SEPST on it and collected some data. I really couldn't see anything out of the normal in the data recording, but since the SEPST doesn't have the ability to record true AF ratio only desired AF, I hooked up my Innovate LM-1 Fuel Air meter to the bike, and also captured voltages from the MAP sensor, the Twist Grip Sensor, and the Throttle Position Sensor feedback to the ECM. It wasn't a lean surge, the air-fuel was just about right on with the data from the ECM. The codes persisted to pop up from time to time. I cleared them and rode on, still surging when you roll on the throttle. That's when noticed that here is no surge if I am using the cruise control. Seems the ECM can control the throttle position but the Twist Grip did not. So I replaced the Twist Grip Sensor and the throttle body just to be sure. No difference. So now I am thinking it is a software problem in the throttle control of the ECM. The bike is out of warranty now, so no more visits to the dealer unless I give them money to "diagnose" the problem. They tried that, under warranty, I don't think they will have any better luck if I pay them. Anybody got any ideas?