ethanol in gas bad for our cars?

Nope. But adding oil to the fuel does nothing to combat that -- except perhaps in the mind of he who does it.
My mind's just fine. Apparently we must have learned chemistry at different colleges:

http://www.chemcases.com/converter/converter-24.htm

Just a reminder, the topic of this thread is "ethanol in gas bad for our cars?" The consensus seems to be yes, and fuel additives are clearly one way of combating the issue.