Octane Fuel Rating

Im having a hard time guessing searching what octane rating my 86 cress uses? I check and it shows premium on the fuel site. But my supra used to take 87 octane same engine. Any help? Thanks.

If it needs premium there will be stickers on your gas lid and sometimes gauge cluster

Damn! When i got it, it ran nice now ihear a little ping/detonation with 87oct i put on it

I just checked it says unleaded fuel only.

Previous owner may have advanced/retarded (I can't remember which) the timing for more power. If so you should run the higher octane.

Designed for premium, will run on regular with light knock. as long as the knock sensor is working, it'll be fine and just return slightly less power and mileage.

I have an mx72 and mx73, and once I started running 91 no ethanol, my mileage really increased. Took about a tank to notice, but after that I've been getting an extra 80-100 miles more a tank than on 87 with ethanol. Best I've gotten on the highway so far was around 412miles out of a tank with the sedan. 390 on 93 with ethanol, got me to do some reading.
main reason why I started this was when I went to build my intake I noticed alot of white powder in the intake manifold. Aluminum is the #1 most easily corroded metal with ethanol.

I tore down half a dozen engines for my X8 engine build and none showed any white powder in the intake or head. I know for sure mine's been getting E10 as long as I had it. I even tried E85 when it was like $2 cheaper years ago (big mileage hit but ran OK) and it never showed any signs of corrosion.