ASA everyone. I need some help. I have 2008 Prius second gen 1500CC since June 2013, It was giving me 16 to 18 Km in the city with normal drive and not live one is suppose to drive prius. Two months back I got I tuned up changed the plugs, changed the air cleaner but after that MY car started to make knocking sound on every speed and the millage dropped down to 9km, then I changed the oil filter and oil “Helix ultra 5w-30”, and filled up my tank with high octane then I noticed that the millage of the car was going up from 9km to 14,5km but still with the engine knocking on every speed till the next tank fill up and suddenly knocking stopped engine was smooth again. Now when I drive my car in a priusly fashion I can get about 17km but after few more stops it just comes back to 14km, the hybrid battery seems ok nothing unusual , I was wondering if anyone could help me with this problem, should I get my car reset with the scanner ? If yes the from where? Javed denso? I would really appreciate if some could guide me.