Before replacing the IAC or TPS try cleaning the IAC valve. It's worked for some of us with the low idle issue. It's easy to do. Take the air cleaner off and squirt carb cleaner into the orifice while cycling the ignition. It's in the 12 o'clock position just in front of the slide.
So far it's worked for me several times.

 

I have an '07 with no engine mods. A was having periodic high idle problems (2000 rpm or more - whatever the rpm the engine was at when I pulled in the clutch) and periodic stalling due to low rpm idle when coming to a stop.

Harley came out with the following Tech Tip specific to 2007 engines: TT410:Big Twin Idle Speed Improvements. The local dealership performed the troubleshooting and adjustments per the TT a couple of years ago. The engine has run without a hiccup since then. I think I'm one of the few that got periodic high idle, at times, and stalling, at other times, resolved by this TT. It might be worth a shot. I have a PDF of it but unfortunately I'm not computer savvy enough to attach it to a post.

 

Iclick if you grind a 1/4 off the end of the bit and use a wrench on the bit it will clear the fins.

 

This describes my problem, exactly.

Could you please PM me the PDF file or link?

Thanks

 

http://www.pdf-archive.com/2011/03/15/tt410/

 

Thanks, nvsteve.

drspencer,

The dealership updated the ECM calibration and adjusted the voltage as discussed in the TT. I cleaned the IAC valve with carb cleaner as described by nvsteve when I was having my problems but it didn't help. Although I haven't had any idle issues since the fix, I clean the IAC valve at 5000 mile intervals as a PM. I figure it can't hurt as long as I use it sparingly and cleanup the overspray when I'm done.

 

I changed out my IAC...be careful when removing the bolts.....one of mine broke off because of the locktight on it. The whole aluminum assy has to be replaced then.....I removed my throttle body assembly and drilled/tapped a new size hole though....used clean rags and cleaned it up very well to keep any shavings out of it.

It was so tight...my easy out tool broke off in it also.

Little bit of a pain....sometimes locktight is not your friend!
Just need one drop when using on small bolts....

 

I don't think my light ever came on, but it started throwing historical codes (P0122), so if I were you I would check the codes anyway. It can't hurt.

Sounds familiar. Mine started with an intermittent misfire that would occur for a few miles, always on the highway in 5th or 6th gear and under light load (~15% TP), then it would go away. It might not return for months at a time, and my first effort at fixing it was to change spark plugs. The problem would go away, so I had my cause-and-effect relationship, right? Wrong! I went through this with three sets of plugs, a new set of plug wires, and changed gas brands--all of which "fixed" it for a while, but it always came back. My $500 tank hose and regulator repair didn't fix it either, but there was a small leak that needed attention. In fact, none of the above were the cause of the misfiring and weird idling. I thought the idling problems were separate issues, but I now think they were all related to the TPS. In that sequence of events I cleaned and changed the IAC, and neither helped.

I thought I had related it to engine and/or ambient temperature, as for months it would only occur after about 15-20 miles of riding in moderate ambient temperatures (~80-85°). In fact, this may have been a factor by triggering the problem in the TPS, perhaps by metal expansion and contraction, but toward the end it was doing it much more often. I should repeat that I also had idle problems that I now believe were linked only to the TPS.

Well, I can't tell you this isn't the problem, as it may well be. Two active threads were going on at HTT ("Stumped" and "Stumped part 2") when my problem was starting to get really bad. The OP had the same symptoms as I was, but when he changed the TPS it didn't fix the problem. His turned out to be a bad o-ring on the fuel-pressure regulator in the tank.

I can relate. My '96 RK never had any fuel or ignition problems in 106k miles of riding. Now I'm blessed with a TPS, IAC, and several other assorted switches and sensors, any of which can cause problems if faulty.

Please keep us posted on your progress, and I hope you find the cause sooner rather than later as you go down the list of suspects. BTW, I should add a couple of items to that list: Injectors or injector wiring. Check the wiring at the injector, as they can become damaged if they're in a position to vibrate against the engine.

I'm not sure this would've shown a fault with mine, as I monitor TP while I'm riding and didn't see any erratic behavior, that is until the very last few weeks. It was reading high, but otherwise looked normal.

 

Never mind. Steve beat me to it.

 

Damn, glad I didn't run into that. Maybe it would be wise to spray some penetrant on the bolts to help ease them out. OTOH if they're clogged with Loctite it may not work its way into the threads. Mine were firm but not so tight I felt they might break. The new IAC has new bolts in the kit, IIRC, and they have a dab of Loctite on them. I know the TPS had bolts and an o-ring in the kit. I didn't do it but would recommend replacing these with Allen bolts to make removal easier in the future.