2001 softail duece fxstdi, fuel injected. starts and runs fine for about 20 mins.then begins to missfire and pop, cannot give it much throttle. i have already changed fuel filter and fuel pump. any help is welcome

 

Sounds electrical, relays, coil, or low voltage.

 

Might be an intake leak. Doesn't manifest itself until it gets up to full temperature. Ride it for a bit, park it at idle, and spray carb cleaner around the intake seals and throttle body. If that idle changes, that's it. Be careful not to overspray into the air cleaner...it'll give you a false positive.

Not sure about the specifics on MM injection but the Delphi has several sensors inside the throttle body that sometimes get gummed up. If it isn't an intake leak, take your throttle body apart and clean everything.

Yeah...could be the coil heating up and dying too. Coils do fail occasionally. Start cheap, if it isn't an intake leak or dirty throttle body, lean towards a bad coil.

Let us know how it works out.