Originally Posted by jeterkm02

You need to stop dispersing any more information on what you feel. An octane rating is only a fuel's resistance to resist detonation. A lower octane level will not cause valves to rattle, or foul plugs/wires.
The only way you could correlate gas mileage and octane rating is if an engine requires high octane such as 91, and you give it 87. The motor will retard its timing to prevent detonation. Retarding the timing, more so than not, will cause a performance loss and you will need more fuel to attain the same power you would have achieved if you had used a higher octane.

If you feel like you're entirely correct based on your "experience", then feel free to debate what i said and answer my questions: how would the valves rattle? would they rattle up and down? or laterally? how would a lower rating foul the plugs? would they end up cold? wet? glazed or overheated? How do you foul plug wires? How do you justify the worthiness of using a higher octane to get a "better burn" when the differance in BTU's between racing fuel (116 octane) and pump gas is only slight.

to the original poster: If your manufacturer recommends for 87 octane, then put in 87 octance. If you wish to "clean" your motor, there are plenty of additives available.
Kris