consulted my friend (the one with 200,000km on it) what thing he use to service the car cuz his one tank can go 700km. mine only 550km.
so conclusion is a lot of things (my engine should be super dirty with oil deposits, so the whole car is not responsive, and not so fuel efficient)
this service interval i switched to Liqui Moly full synthetic + engine flush + additive (to reduce friction)
this is what i did with it, first spray Seafoam valve cleaner into intake and rev everything to clear valve.
then drive to workshop to ask them do engine flushing.
OLD engine oil (7000km) after adding flush and running it for 10minutes. like KOPI-O
then because i watched some videos that do flushing on cars that never done it before (run 100,000km never flush) they had to flush - drain - add new cheapo oil to run 2nd round (run 10-15min) then drain. THEN only add in LIQUI MOLY.
Basically DRAIN THE OIL TWICE if not the new oil added will be instantly dirty !!
this is the sacrificial cheapo 4L engine oil (new engine oil just run for 10min) that i added in after draining the oil.
pour new oil in immediately turn dark, dirty like teh O.
after that add in LIQUI MOLY 5w/30 and additive.
now the car is very responsive, can always feel the acceleration even step on the pedal a bit !!!!!
Steps
1. seafoam clean intake valve
2. pour in engine flush and run for a while
3. drain 3month old oil
4. pour in new sacrificial engine oil and run for 10min
5. drain 15min new oil
6. pour in new LIQUI MOLY oil and additive (MOS2), change oil filter.
so much better response. step a bit power immediately come
Many types of cleaning can do. Fuel additive, intake valve, engine oil additive (these are without opening engine top cover)
excellent info.