Ok thats weird! Fuel pump problem (possibly?)

Well for the last few miles (from about just into the red) the engine was idling low again, I was going to adjust it again after I'd filled it up so engine could get warm.

Fill it up and guess what? The idle is back to 950ish RPM up from about 800.  :?

What could this be? Fuel pump on the way out? I have to say it felt ever so slightly more gutsy on the way back than it did while in the red.

Also what size tank should it be? Haynes manual says 9.9 Imp Gallons 45 liters yet im half way in the red and only fill up by 33.98 literes meaning 2 gallons is still left?  :dontknow:

It did 35 MPG tho so im happy with that.

So questions are:

1. Whats causing this low idle and possible low engine power at low fuel levels?

2. Why is there 10 liters (in theory) still in the tank?


Cheers