As you are running premium fuel -- I would say no, it is not necessary. If you were running regular I would probably say yes as there are usually less detergents in the lower octane fuels.

I treat my RX to a bottle of Techron once a year.

 

So just to reiterate; as long as I run any premium gasoline, from any gas station, a bottle of Techron once per year is sufficient?

 

It`s only about a $4.00 difference between reg.and prem. fuel per tank.

 

As my father always tells me....own a premium car, stop *****in about premium gas.

I always got worse mileage on regular gas in every car I've owned that required premium. It works out to nearly the same cost. You might as well put premium in there.

 

Plus it will run as designed.

 

So is the RX meant to have premium? The owners manual says regular and then says premium if you want optimum performance? So, okay I realize that optimum is optimum but is that the same as "run as designed". It just seems like needless obfuscation to me.

 

Premium fuel is required for the Lexus RX350 because of the higher compression ratio. Your 2004 RX330 will run fine with regular.

 

Regular is what is recommended for the '04 like Rainbird said. I went midgrade most of the time. Test out a few tanks when it's warmer to see which grade is better for yours.

 

87 Octane and fuel cleaners every 4~5K miles. Working like a charm.

 

Premium, Costco, Sams or Arco/BP, no cleaner no problems 47K.
Jeff

 

The bottle of Techron is optional. No scientific foundation one way or the other. More an item to make one feel good about one's actions. I do it as my RX does not always get a chance to see time on the highway to get a good run and blow out any carbon.

 

you guy`s man,Just run what is recommended which is 91 or higher. Yeah it`l run on 87,but that`s about it. Dont expect any real performance from it then either. I.E passing power,pulling hill`s with the A/C on in the summer time,etc.

 

I've been using Shell V-Power for years and haven't needed any injector cleaner. I do get 1.5-2 MPG more on the expressway when running premium in my RX330.

 

the Lexus is a premium vehicle, yet people dont want to to the same re; the fuel to keep it running like it should. Years down the road skimping out on the fuel may come out to bite them.

 

Premium really works better with our cars.