5S-FE fuel?, What fuel to use? Options

[UVZ164]

Hey guys, I'm kinda new here and not sure if this is the right place to post this.

I did a search but couldn't find the specific answers I wanted so I thought i'd ask.
I live in Sydney Aust and the fuels available to us are: E10(10% ethanol) 91 octane, and regular 95 and 98 unleaded.
I recently bought a ST204 ZR which is the equivalent to the American GT. It runs the 5S-FE.
The guy I bought it from told me to steer clear of the E10 as it will ruin the engine. As my wallet isn't that deep I decided to give the cheaper E10 a go.
After about a month and a half of running the E10(i'm assuming the previous owner used 95) i'm beginning to hear a noise almost like tapping when I rev the engine above 3k rpm and just let it decrease naturally. As it never made this noise before, could I be right in assuming that the E10 is doing something and possibly ruining the engine? The owners manual states that 91 octane is as low as you can go but it doesn't say anything about Ethanol.

Thanks in advance,

Reece

[mandrek]

in sorry if i come accross like an ass here, im not trying to. but it gets so frustrating to see the same ,nay-saying, talking points about E10 and further more E85.. the same disinformation and misinformation by people who do want to accept change... there is a reason why E85 has taken the import seen by storm.. because it WORKS.. and its a hell of alot cheaper than having to run race gas all the time..

as to the OP. i appologise for the OT post. and yes, much as i am finding out on my current motor break-down, odds are that the sound you are noticing are just due to a 15 year old car showing its age.. plz if you could post a vid or at least a sound clip, im sure that there is enough experiese on this forum to help you out.. once we get some more information..

good luck