My '01 still gets about 20mpg. I usually get about 290 miles per tank.

 

I've bought RX 300 '98 recently, and I have more than 20mpg on highway, but only 11-13 mpg driving in city !!
So I have some questions
I just checked CEL's and I have:
P0141 HO2S Heater Circuit Malfunction, Bank 1 Sensor 2
P0171 System Too Lean (Fuel Trim)
P0325 Knock Sensor 1 Circuit Malfunction
P0330 Knock Sensor 2 Circuit Malfunction
1) Dirty MAF should cause any CEL, or MAF can be dirty, and no connected CEL?
2) Can this problems cause bad mileage in city, but not in HW?
I will check this HO2S heater resistance today. I know how to do it, so there is no question
3) I don't know where are knock sensors, and how to check it - can anybody help me, how to do it ?
4) I didn't clear MAF sensor and IACV yet - may it be reason?
5) Also I didn't change transmission oils (only engine), but A/T, and diffs oils looks fine, where is plug to check transfer case oil?
6) P0171 can be caused by P0141 or dirty MAF? What else should be checked?
[EDIT 2010.03.30]
I cleared MAF. I replaced oxygen sensor - P0141 and P0171 disappears. Now I have to check knock-sensors.

 

I am getting 20/22 on the highway and about 3 to 4 less mpg city. Now my RX300 has been babied for 10 years (bought it from mom and dad) and it only has 47k on it. My 330, if driving with cruise control set to 65 and the terrain being fairly flat, will get 25 to 27 mpg per the trip computer which is pretty accurate.

JBL

 

Hi ilanh, I am now getting around 6.4 km/L.
I used to have 6.8 km/L before. If I travel on Highway a lot, it can have average 7.2 km/L.

However, it drops to around 5.8 km/L these days and I am now finding out the problem.

 

Let me know what you found.
I used to have 5.5 km/L and for the past 6-8 month dropped to 4.4 km/L and i can't find why

 

I have a 2000 AWD and i'm getting anywhere from 18.9-20.2 mixed highway/city driving. I live in Utah and when its snowing, the milage goes down a little. But its not too bad.

 

I get 16 mpg combined, but that is Chicago driving. Stop, go, stop, go, stop, go... Gotta love the 1940s roads we have to drive on around here along with the 1960s traffic signals none of which are coordinated with one another trying to handle 2010 traffic.

 

Hi Chau,
Is ur problem solve??
Mine also the same, about 6km plus/L in city driving, if only highway can get 7km-8km/L.

But some of my friend can get 10km/L in highway.
If your finding can make FC better plz do share here, thanks

 

I'm happy driving my RX as a daily driver because it gets 20 mpg vs my FZJ80 Landcruiser that gets around 12mpg.



Its all relative I guess

 

I changed my CAT and got 18 MPG!

 

what was you mpg before you changed your cat??
And did you change both cats??

 

I own a 2001 RX300 with 177k mile on it and after doing a major tune up (plugs, wires, fuel filter, all air filters, pcv, anything i could think of: new vacum hoses) 2k miles in,I suddenly am getting 17mpg on the highway. I use to get 25mph on the highway. Then on top of it all, I'm getting the imfamous RX transmission problems. not going into gear, staying in gear, slipping gears. Way I see it, time to dump it before it leaves me stranded on the road..... again. I guess I got my $$'s worth out of it "NOT!!!!." I'm truely thinking of going back to a volvo. At least it lasted more than 250k miles. And from what I hear from my mechanic, its still going....

 

Kinda sounds like where i live, And I`m so tired of hearing the "we have no money Bull****!!"

 

One thing i would recommend for any car of any age is a decent Earth wire to the real earth the engine not the chassis. Just adding a real earth generally give more power to older cars that may have brittle earths. As far as fuel consumption goes with a heavy car and a small v6 engine i dont expect to ever get a real good fuel ecconomy that being said it has a lot more pep than some other awd/4wds etc only because they all fall into same bracket.

 

Say what??? I get it that a good ground/earth is important, but how does that generally add power?