Why does the manufacturer recommend 87 octane gasoline when the engine runs like crap with it. When put regular gas, the engine makes rattling noise and pinging noises and acceleration is horrible. Gas mileage also suffers. The same thing happens in my wife's Rav4 which has the same 2.4 engine. When I put premium fuel the engine runs smooth, gas mileage is better as well as power and acceleration. I called Scion and Toyota and the couldn't give me a direct answer. Any feedback would be helpful.

 

most people are too cheap to put 91 octane
I've always used 91 figure its only $2.20 more to fill up tank with better gas.

 

Then why does Toyota/ Scion recommend 87 octane when it runs like crap. They should recommend 91 for better efficiency. I had a Matrix Xrs and the recommended fuel was 91. The gas attendant once filled it with 87 by accident and the car ran horrible. Needless to say I didn't pay for that tank of fuel. LoL

 

The 2az-fe is a low compression, low horse power engine that only revs to 6500 rpms. Its designed to run on 87.

If you need higher octane to run properly, it might be time to seafoam it.

 

What's seafoam? I've never heard of that.

 

I have used Seafoam on a number of my vehicles. I cannot prove if it actually works or not, but seems to help clean the engine. Lots of folk swear by it.


I use 87 octane regularly in both my 2011 xD & 2013 xB without any ill effects, so I don't pay extra for 91 octane.

 

I'm gonna have to look into that. Thanks for the info.