Ok, first off, I already did a search and I did find one person that had posted the same problem, but it didn't show a resolution. So, maybe I'll have better luck.

2002 Road King /w 50k and EFI.

idle's good, accelerates good, but when I'm running steady throttle over 2200 rpm, it starts to miss. The longer I ride it, the worse it gets.

I figured fuel filter as it's never been changed. So, new fuel filter, new lines inside tank, new plugs and plug wires.

Test rode it about 2 miles, ran great. Decided to take it down to get gas, it missed twice on the 3 mile ride. Took the long way home after refueling and the longer I rode it, the worse and more frequent the miss got.

Not sure where to go from here. I'll check the air cleaner tonight to make sure it's not plugged up and I'll look for any vacuum leaks.

Does anyone have any idea why it would do this? Battery cables are tight and groung is tight and both look to be in good shape. Don't know if this is going to be electrical or fuel/air.

Much appreciated for any help or ideas you can give me. I'm about ready to throw a road flare in the gas tank. haha

 

I have a TTS Mastertune so this may not be a fair comparison, but my 07 Ultra would start out fine and after it got totally warmed up it would do the same thing you describe. The longer I rode it the more it missed. I was going on a trip to the mountains and wanted to richen it up a little. I downloaded a map with a little richer mixture and the miss was gone.

Didn't go back to the original map so I am not sure if it was just too lean of a mixture that only showed up after it was warmed up, or if the original map may have somehow gotten corrupted. I would have to think it is the former.

 

Thanks for the reply. I never thought about the mapping getting corrupted.

I'm probably going to have to take it to a shop to at least troubleshoot the problem. So long as I know what it is, I can fix it. But I could spend a ton of money just blindly replacing parts. haha

 

Curious as to an outcome. My stock 06 Street Bob did the same
thing this morning on the way to work. I have an appointment
for it's 5k mile service on wednesday. Good luck!

 

Nope, haven't found a resolution yet. I cleaned out the throttle body and around the throttle position sensor. It ran good for about 40 or 50 miles then it started doing it again.

I have a number for a mechanic that may have some ideas for me that I'll be calling later on. I'll post here if I find a resolution.

 

Have all you guys checked the spark plugs? Wires, boots?? Wires to coil.
Thats just about the first thing I would be looking at.

 

First things I changed was fuel filter, top fuel tube from pump to filter, plugs and plug wires. No effect. I was hoping though. haha

Last night I put in a new Throttle Position Sensor. It ran fine for the 15 miles to work, but until I've burned up this 3/4 tank of gas and it hasn't done it, I won't consider it fixed. I think it's just trying to lure me into a false sense of security.

If this doesn't fix it, the next part I go after is the MAP sensor...according to the dealer, that is a fairly common replaced item after 50k.

 

You do not clarify if you checked plugs/wires/coils.

I would go to plugs first...in your case...next. The miss a partially fouling/failing plug can vary greatly. Wires you can check easy with a multimeter...just be sure to wiggle them around when checking. Coils can develop a crack that worsens with heat. Not much rocket science going on in a Harley and looking at fuel has not solved it yet for you.