2010 triumph rocket 3 starts and idles great but starts misfiring at 3000 to 4000 rpm then is fine when you pass that range she's had new plugs fitted and coils seem fine this problem start after she had sat for afew days but was running great before this any idea's on what the problem is would be great
Yep
Bend them in a bit more so they hold better.
Or just ditch the 1960's old coil bs and go to the overhead coil packs. It's a good upgrade on its own and is about $150 and 3 hours of work.