Lex,did you notice a difference with the fuel?

 

It jumped up a maximum of 1 mpg and is holding at a .8 mpg improvement, but the RX feels like garbage on acceleration, we'll find out tonight as I plan to head to the track, though I am a bit above my norm on the tank level, between 1/4 and 1/2 tank, so will have to make an adjustment.

Tomorrow, I plan to install an air filter and also add that Liqui Moly additive I mentioned that will help repair the piston rings and see how it does tomorrow night again.

 

Are you burning oil,from not using an air filter? It`s tough to find a good mechanic in a can, at least for some applications.

 

Well, I used to have consumption problems with Mobil 1 5W30, but haven't really had oil issues so-to-speak, rather with gas and power. I have been using Restore for the cylinder walls, but really haven't found a fix for piston rings, but we'll see tomorrow if my track buddies are pulling my leg or not, as they tell me that stuff works like crazy glue, immediately.

Yeah, no engine filter adds up to issues, but at this altitude, I have had MPG issues with the filter.

 

Then again, tomorrow I will be adding an air filter.

 

You guy's have it good - over here in the UK it costs the equivalent of $140 to fill the tank and from next year the road tax shoots up to $880/year !

 

so it has been probably a month since I replaced my air filter...

I just want to report that I'm getting 19mpg. haha Something has to be wrong. It should not be this good... I wonder if my air filter really makes that much of a difference.

 

Oh, this should interest some of you. For the trip out of Mexico City to Tampa, we ran 25.6 mpg and that was with a fully loaded down RX (I have two moderators who can testify to the load).

 

25.6mpg on a loaded-up awd RX !!
Wow...Hey Lex, are you running stock size tire?

 

235-70-16 is the size I am using.

 

That's some awesome mpg.

My '99 RX300 AWD gets 16 mpg city/22-22.5 mpg hwy. Measured multiple times. 90,000 miles on car. K&N, clean MAF & IAC. What are the published numbers for these cars?

Lexmex: I skimmed your Lexus pages. What mods do you think helped the most in improving your gas mileage? Which were the most cost-effective? Thanks.

 

18 city/22 highway is what I have heard the most for the RX.

Best bang for the buck is a direct flow muffler. The real problem with the exhaust it the muffler at the end. The resonator underneath the vehicle is direct flow and the only other hindrances are two precats and 1 cat, but the real deal is that fat muffler on the end, very indirect. The BMW muffler I have on there now is indirect as well (noise reasons due to my modified exhaust), but has a much better flow rate due to a better design for my type of dual exhaust.

 

Thanks. I'm going to maybe look at Magnaflow direct flow.

 

I have a 1999 RX 300 FWD with a 160,000 miles. Average for city driving is around 18 and highway gets 24 mpg. I normally put 87 Octane. Mileage does improve if you put an addititive though