Hey guys,

1998 S90, it has 16X,XXXkm's. I drive all highway 90-110km/h. In the book it sais to use premium 94 octane but it sais you can also use 87. I do not drive the car hard so is it ok to use regular?

Thanks,

 

Regular works.
Reg

 

reg. work. but when you go to pass some one you might hear a little knock when you floor it.

 

It should not knock..............the ignition retards and there is also a knock suppresor on that auto. You will find the performance down and indeed, in the hot summer weather it is better to use premium if the performance is severely affected. But, regular will not harm the auto.
Reg

 

regular is fine.