I have a Road Glide 3 with M8 114. Has Vance & Hines slip ons and a S&S air cleaner. So I installed a Vance & Hines FP4 tuner and set it up to the proper tune for that setup. Worked fine. Then one day I'm out riding and stopped for gas after ridding 150 miles. When I restarted it was in limp mode. I was 100 miles from a Harley dealer on a Sunday. I let it set for a while and it started and it was fine except for a check engine light. Got home and checked the codes. One said that the throttle sensors did not agree and it went to limp mode. Called support at V&H and they said it was mechanical. So I just thought it was a fluke. We went on vacation and on one of our rides it did the same thing. Only this time I had stopped and let it idle for maybe 5 minutes. Again limp mode right when it was running. Waited 10 minutes and restarted with check engine light on, rode back to motel. Same message Throttle sensors didn't agree and went to limp mode. I took the tuner off and reloaded the stock setting. Put my stock air cleaner back on and I have ridden about 1000 miles and no more problems. I am beginning to think it's the Vance & Hines FP4 tuner causing the problem. Anyone else had trouble with their tuner. I had a FP3 on my 15 Ultra Classic and never had a problem. Opinions Please.

 

If you flash the stock map back and the issue goes away it is likely the map. Perhaps try a map built for quiet baffle for the same exhaust or Have V&H suggest an alternative map that was built using an exhaust similar to what you have installed. Any other changes or modifications that occurred when you installed FP4?

FYI according to Bryan AFV tables are updated after about 50 miles and a key cycle and that seems to align with your issue.

Have never used FP4 but have never had any issues with any of our FP3s. With Bryan having left V&H I am not optimistic about FP4...

https://www.hdforums.com/forum/ignit...138-codes.html

 

My FP3 was great and rode with it for 31000, Not so sure about FP4

 

We have used them on four bikes and never had an issue. Great results in each case.