FrOregon

I have recently reached my 3 months anniversary for my 09 TSX (Auto with Tech package). I previously owned a '05 Tsx and used regular gas without any noticeable problems. So with this experience, I used regular for several fill ups on my 09. I noticed a ping/knock (loose bolt sound) at around 2000 rpms so read somewhere to use only premium. After my next premium fillup, sound was drastically minimial and pretty much gone. So just to make sure, after couple of premium fill ups, I went back to regular. Needless to say, that knocking sound came back. So, once again, went back to premium and as expected, sound was gone. Ever since, I am going to stick wtih premium.

I am not sure if this is just in my case, but with this experience, I will stick to only Premium gas for my TSX.

kalmario

At what octane was the regular gas?

iTimmy

This doesn't surprise me, but is good to know someone has tried and verified that premium is truly required.

nj2pa2nc

One of the main complaints from other owners of 09 tsx was the pinging/ knocking they were experiencing. It did not matter what octane gas they were using. (majority had automatic transmission)

cmasterchoe

noob question, in another thread a poster mentioned that the ECU would automatically adjust for regular gas. How long does it take for it to do that. Is it instantaneous or gradual (ie more than one fillup with regular).

09TSXMN

It is instantaneous. There are knock sensors that communicate back to the ECU. The ECU then adjust the timing of the spark, which diminshes the power.

katmai

Hmmm I've used regular without any problems.

Tigmd99

Since our cars get good MPGs, why not just use Premium and have no worries? Premium is not that expensive these days, certainly a lot cheaper than if Honda gave us a diesel!

nj2pa2nc

Use what works for you-

LuvMyTSX

Diesel was actually only about 20 cents more than premium at the station I last filled up. It has come down tremendously,but will likely go back up again once the economy improves, since industry will start to use more diesel then.