I just bought a 99 runner 3 weeks ago 1 owner 128k pretty clean for a 99. So far I just did an oil chance and replaced a 2 o rings by the speed sensor since they were leaking. I replaced the rear springs and rear shocks. Front shock are next. Should I do any preventive maintenance to it?? On 3 fill up it gave me 19.80 mpg, 19.95mpg and. 19.90mpg mostly city driving!!!!! Pretty good in my opinion. Should I leave it like it is or should I change anything????