Run a bottle of "Injector Cleaner" through occasionally.
I used to own a Mk3 XR3i (Real Boy racer car) and it lost some of the OOmpf it used to have.
When I get my paper on the way home from work, to a traffic island in the "Private" road
If what I'm driving is on song, I will be doing 100mph.
My little test track.
The XR3i was down on the 90mph range, a tank of fuel with injector cleaner and it was back to over a ton, only ever bettered by the FRP
The FRP is just finishing off a treated tank at the moment.