Switch to 87 and just listen out for 'pinging' from pre detination (spark knock). The engine shouldn't ping on 87 as that is what it was designed to operate on, and the F22 doesn't have high enough compression to normally warrant higher octane fuel... but just in case. Predetination puts a lot of stress on the engine internals.

I actually use mid-grade in my 96 which has almost 209,000 miles on the engine. I started hearing a little pinging one day (the car already had over 150k miles) and rather than try to dig into what the 'problem' may have been, I just switched over to 89 for a few cents more and haven't had a problem since.

I run 87 in the 2007. If it pings, it's going to the shop.

 

My drivers side passive restraint went so I'm going to have to wait a week for the tune up oxygen sensor change. I found out through the search feature that the restraints are warrantied for life so I'll make an appointment with Honda. If they can't fix it this weekend then I'll get it tuned up and wait till next weekend to have the seat belt repaired. But I'll be honest that fuggin bell is irritating as hell.

 

I'm runnning 89 as it's seems to run better on 89 than 87, no pings but engine seems to idle smoother. I'm still getting a CEL every so often, it only comes on when coasting while in gear. But it never stays on. I'll mention to the mechanic when I get the timing belt changed this weekend or next.

 

Almost 2 years to the date my 91ex is no more.. Needs a head gasket, master cylinder (I think, maybe a brake line. Either way it's losing fluid) and a radiator. In 2 years I had the alternator, slave cylinder, and water pump and timing belt done. She served me well and often under duress as I rode her hard and often neglected her. Not sure what to do with she yet. Let her marinate in the garage until I decide.