I have a 1997 SSEi with 67k miles on it. Can I put regular unleaded (Octane 87) in the tank even though it calls for premium unleaded (Octaine 93)? With gas prices the way they are, I put regular unleaded(Octane87) in the tank. I have been doing this for a few months and I don't hear any pinging or any noise from the engine. Will I cause engine problems long-term using regular unleaded instead of premium unleaded?

You can cause long-term damage to the engine, and you're actually getting worse fuel mileage as the PCM is pulling timing due to the lower octane (more knock) fuel.

99% of the SSEi owners here wouldn't dare do that. Myself among them. 92 minimum in both my cars.

What about 87 in an SE? =)

that is recommended

Will you always have a way to scare people

If his knock sensor fails, he CAN damage the engine. You are about the only dissenter on this issue. The argument rages, but at the same time, why take the chance?

I am running mid grade 89 in my 93 SSEi, but that is the lowest I will go. About once a month I run premium in it just so it remembers what it is like.

does your fuel mileage suffer?

The way gas prices are now, at $.10-.15 more per gallon to upgrade to premium over regular why not just buy the premium? I know it'* still insanely high (I'm as PI$$ED off as anyone) price for fuel, but if you consider that that is still the same price diff as it was 5 yrs ago when regular was $1.05/gal and premium was $1.17 (at least that'* what it was here) it'* worth the price difference now, almost more than ever.
I myself will not go below 91 octane in any vehicle I drive, unless I know it runs better with lower octane.
I say go for the gold and don't settle for bronze either.

Dissent? Not really. With that statement right there I totally agree, especially with the emphasis you provided. To me there'* a big difference between just saying "you can damage your engine" and stating that if one engine component fails you could damage another. The engine is built in such a way that 87 octane will NOT damage it. If engine components are failing, however, you do run a risk. But that'* the same with anything. If my MAF is failing I run a risk just driving it, same with the o2 sensor, egr, or any number of other parts. With that I wouldn't simply state "if you drive your car you can damage it" on an assumption of failing sensors...make sense?

One statement causes unnecessary fear while the other actually informs him of the risks involved.

Interesting to me there isn't the same fear of using a K&N filter, which many feel has a more direct effect on a sensor which could in turn cause engine failure.

I'm not trying to split hairs, but that'* the only reason I say anything on the subject anymore. I'll be quiet now