OK, I'm new to the forums and have looked around for similar threads for my issue but haven't found anything that appears to be the same issue. If I missed something I apologize in advance.

I have a 97 FLHTCUI that the engine cuts out randomly when I go over rough bumps or under heavy acceleration. Again it is random but appears to be gradually getting worse over time. On bumps it tends to do it more often when riding two up, but still does it when I'm alone. As far as I can tell most of the accessories (radio, speedo, tack, gages, lights) continue to work fine and don't cutout. However, if the cruise control is on it kicks off. I'm looking for some advice on where to start looking. Below is some additional information.
- Stock Magneti Marelli EFI
- Power Commander III
- Engine, intake and exhaust have been modified (not that it should matter)

I'm familiar with cars and have worked on them for years (25+). To me it's like it is dumping fuel into the cylinder and then missing. This creates a hesitation (1 sec or less) and then it kicks back in and most of the time back fires thru the exhaust pipes. Almost like power to the ignition system is cut briefly. For the rider and more the passenger this is a double whammy; you slow down and then wham you quick speed back up. If you're not holding on it can really get you. My wife has the death grip on the back seat handles. Any help is appreciated.

 

Start checking all your electrical connections and grounds.

I'm not computer savvy on the HD EFI system, but from my experience with the automotive junk, if you lose continuity you're going to have issues.

 

I have a 98 wide glide that had simular problem, except when mine would cut out I did notice a drop of lights/milage indicator, I checked my conections and found that the battery cables had loosened up and I also found loose connection on the 30 amp circuit breaker(main)tightened all and have had no issuies with that since. good luck.

 

Welcome to HDF. This is likely to be one of those mysteries that will take some dogged determination to sort out!

There is an excellent thread by jgcable where he traced through electrical problems on his bike, which is worth a read!