I went to PWD yesterday, there were traffic blocks, so average was around 12.5. On the way back, not many jams, so avg. was 15.5
On cold start in the morning and 4Km run, i get 8.5-9kpl.
So overall, 10-11kpl in the city driving is fine.
Regarding RPMs, those need fixing (Should be around 1000 on cold, 700 when warmed up). Giving problems now or right from engine swap?
Check IACV and MAF as a first step. Then air filter, throttle body, TPS