e-man

Hey guys. I'm just checking in from over on the GS forum and I have a quick question. Is there any known problem with the RX developing unusually bad gas mileage later in life? A friend of mine has an 01 RX300 and out of nowhere the gas mileage on his car has dropped from 15 mpg to around 10 mpg for no apparent reason. He seems to think that this is a well known and documented problem on the RX and has something to do with the MAF, A/F or 02 sensors, but he really doesn't know for sure. Has anyone encountered such a problem and is there fix for it? I'm sorry I can't be more specific, but that's all the information I have. Thanks for any help you can lend.

e

Lexmex

Dirty MAF or just driving pattern are most likely culprits.

With MAF sensor can clean with electrical contacts cleaner or computer keyboard cleaner (there is a red diode and two wire visible inside the sensor). With driving pattern, there is an EFI fuse in the fusebox in the engine bay that can be pulled, but what I would highly recommend is to take off both of the battery cables for at least 15 minutes.

salimshah

I have not heard of low mpg as a prevelant problem. We have had a few posts about getting below 18, but not around 10. I would definately put that in an abnormal catagory.

Salim

Francis

What's the milleage? fwd or awd? what's the psi of the tire pressure? I have 36 psi in front and 34 psi in rear. Increase tire pressure may help.

99' RX 115k miles, fwd, 21 mpg(95% freeway, 5% city)

salimshah

The orignal question was exploratory (I think)....

Salim

e-man

Thanks for the responses, guys. I just talked to my friend, and apparently I didn't have the numbers right. He claims that he used to get 20 mpg, but all of a sudden he is now getting 15. He has the AWD model and has 75k miles on the ticker. His tires are all filled to 33 psi.

Personally, this doesn't sound like a problem to me at all. 15 mpg on an AWD SUV sounds about right to me, especially during the cold Chicago winter.

Anyway, I'll tell him to have the MAF sensor checked out. Is there anything else that anyone can think of?

magorkerby

I have the same issue. The trip computer on my 2001 RX300 would register MPG of about 20 when I lived in Texas. I moved to CA 2 years ago and my mileage dropped to 15 or 16. I have a feeling it is because CA uses higher ethanol content in their gas, which reduces the effective MPG.

lexus114

[QUOTE=magorkerby;6758713]I have the same issue. The trip computer on my 2001 RX300 would register MPG of about 20 when I lived in Texas. I moved to CA 2 years ago and my mileage dropped to 15 or 16. I have a feeling it is because CA uses higher ethanol content in their gas, which reduces the effective MPG.[/QUOTE]



Makes so much sense right? This stupid government of ours wants mpg`s,mpg`s mpg`s. Yet they castrate the vehicles by making up this crappy fuel,so everyone`s millage is in the toilet.? Today`s vehicles already burn as lean,and clean as they can. What more do they friggin want!?

Lexmex

Welcome to the Club.

So true Lexus114 on your comments. I have the ethanol issue here, too. Not fun and not necessary. We used to have emissions testing in certain counties in Florida from 1991 to 2000 and it wound up costing more to administer than it took in. Ended up doing nothing because the technology improved over time and we have a flat state with a lot of wind. Granted, ethanol per se might be cleaner coming out the pipe, but you have to burn more fuel to make up for the crappy MPG you get by using it. In addition, vehicles are so weighed down with umpteen safety features, emissions devices, etc. (not blaming Lexus for this, they probably did as good as they could do), but the government regulations stranglehold them.

C-Stone

1. As mentioned, clean the MAF sensor. It's easy. See sticky on top.
2. Replace Air Filter. It's easy.
3. Clean IAC port. It's pretty easy. See sticky on top.
4. Also, I had an issue at 125,000 miles with the front rotors being warped. It required new rotors, pads, and cleaning and lubing the slide pins (they were dry and probably caused the pads more friction reducing mileage.) Not so easy, but fun.
5. Elect government officials who understand/encourage personal responsibility and freedom from restrictive government laws. HARD... but not impossible.