mixing different octane gas...good or bad?
i've gotten into the habit of putting 89 octane gas in two fillups, then on the third fillup i use 93 octane. i'm a cheap bastard and prolly not doin any good for my car, but is there any real harm in this? gas in my area has been as high as $2.80 at one point, now it's around $1.35 a gallon. let me know. thanks.