AdBlock Warning

Parts of this website do not function properly with AdBlock enabled on your device. To get the best user experience on our website, please disable Adblock for this website (domain) on your browser.


2000 Rx300 Loss Of Gas Mileage

4 posts in this topic

Can anyone help with a sudden loss of gas mileage in a 2000 RX300 AWD. It dropped from just below 19 MPG to 16 MPG almost over night. Have cleaned the mass airflow sensor and changed the thermostat - was heating up slowly. Any other ideas?? No trouble codes. Runs well.

1 person likes this

Share this post

Link to post
Share on other sites

checked the usual, tire pressure, air filter, and dont forget the change in fuel from winter to summer blends....With no cel lights hard to diagnose

Share this post

Link to post
Share on other sites

Just had the CEL come on this morning on the way to work. Code 1150. I believe this is the Air/Fuel ratio sensor on the front bank of cylinders. Bet that could make a difference in mileage. Thanks for the input have checked all the other typical culprits. Was about to remove wheels and check for dragging brakes.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • Wrong O2 Sensor?
      By matthewlswanson
      2003 RX300. Got the trouble code for the Heated O2 Sensor (Bank 1 Sensor 2). says I need part number 
      I believe them so I bought the same exact part from Amazon even though their site says it doesn't fit, thinking the Lexus site will know better.
      Got it installed fine and cleared the codes but the code keeps coming up every time I clear it. Did I just waste $140? Why would one site list it as fitting and the other doesn't? Could it potentially be another issue?
    • 2001 Lexus Rx300 - Need Advice On Oil Weights
      By sheffield_rogue_jr
      Hi fellow Lexus enthusiasts. You can skip down to the bold text if you do not want to read the background of my post :whistles:
      I recently drove my 2001 RX300, which I had acquired last October, on a road trip between Chicago, IL and Toronto, Canada between July 16 and July 25. The only maintenance-related issue that had to be taken care of, an oil change, was completed. I took the car to my local mechanic a couple of weeks before we left and I had him test-drive for a few blocks. He stated, based on his observations, that the car ran well and could be trusted to make it to Toronto and back in one piece.
      With about 137,000 miles, this car ran like a top with no loss of power, no transmission jerking, and got roughly 19-20 mpg the entire way with the a/c running at full blast. Driving around Toronto, my mpg went down, but the performance stayed just as well as it had been along the highway. However, a few days after we got to Toronto safely, I was exiting the highway (the famous Highway of Heroes) and, coming to a stop at the end of the downward-sloped ramp, the Oil Pressure light came on for roughly one second and then went out. Initially, I attributed the light to the steepness of the ramp, but I was disconcerted enough to go back out to the car the next day in the morning with a paper towel and pull the dipstick.
      I popped the hood, drew the dipstick, held it level to my eye, and my jaw nearly dropped. Yep. The dipstick was as dry as the Grand Canyon, with not even a single drop on it
      That same day, I picked up a jug of Mobil 5W-30 synthetic at a local auto store and added right up to the top mark on the dipstick (thank god I had a funnel with me). I dreaded that I would have to repeat the process when I got back to Chicago; when I did so (the dipstick was dry again when we got back), I got the same weight, only as mineral, and only added enough to bring the oil level near halfway between the two marks. Again, there were zero issues related to performance along the way back, and it still amazes me that this is possible. Unfortunately, it never occurred to me to check the oil level at any stopping point along the way in either direction, so I have no clue what the burn rate is .
      Here in Chicago, the car often sits for days at a time in the same spot on the street if it's not winter, as I prefer to ride my bike for the fuel economy B). I would have noticed fresh oil spots under my car if there was a leak, and (with the exception of a FEW start ups) there is no smoke coming from the tailpipe either in city or on the highway. To be specific, there is a small amount of bluish smoke upon startup, but ONLY once in a while - it does not happen each and every time the car is started.
      Yesterday, I went back to the same mechanic to tell him about this little problem. He replied that, as there is no leakage, the engine is burning up oil in small quantity, which was not obvious until my trip. I was advised by him to switch to a heavier oil at the next change to reduce the likelihood of it getting burnt.
      A couple of questions to you, for those of you currently running oils heavier than 5W-30 in the RX300: how heavy have you gone without appreciable decline in performance? How heavy is it possible to run and still be able to operate the vehicle in the winter? (keeping in mind that Chicago winters, although not as cold as the Arctic, are certainly powerful) And lastly, is warm-up time affected badly by a heavier oil (both in summer and winter)?
      Any pointers that I can get are highly appreciated. ^_^
    • Preventive Maintenance & 90k Service
      By Lexus Luddite
      I obviously have a low mileage RX300 since it's a 2003. I'm the second owner having bought it certified from a Lexus dealership back in 2006.
      I recently moved and found an independent shop with fantastic reviews that specializes in Japanese cars. They've quoted $950 for the 90k service including changing the timing belt.
      I'm definitely doing the timing belt because mine is 5 or 6 years older than most who were doing their 90k service on this forum. I don't want to risk major engine damage and the car is still in great shape. Aside from regular oil checks (use synthetic oil BTW), my only maintenance costs in nearly 10 years have been exhaust related, ball joints & sway bars, tires, brake pads and a battery. Not sure if it's been a major contributing factor but I'm someone who lets the engine warm up in every season - especially winter - so maybe that's helped reduce engine damage.
      My question is if I plan to keep the car for another several years should I replace the water pump and thermostat too as a preventative measure and since my car is 12 years old and I probably wont put more than 5 to 8k miles on the car per year. Are there other items you would consider too?

    • Ignition Coils: To By Aftermarket Or Not?
      By rx300inCalifornia
      Hello All,
      So I have been looking at replacing ignition coils on my 2002 Lexus RX300. Found a few places including my local Lexus dealer who wanted $110 each. The Lexus Dealer part is made by Denso. The links below found parts for various amounts. Anybody have any excperience with buying ignitoin coils from other manufacturers:
      1) Denso Sprk Plugs from Ebay: $65.95 each.|Model%3ARX300&hash=item3a800a191a&vxp=mtr#vi-ilComp
      2) Genesis Auto Parts is the store and Brand Name is :Silla: It is after Market Part and is for $16.49 each. However shipping for 6 of these is $48... They ship these indvidually. Go figure...
      3) Denso spark Plugs from Local Lexus Dealer: $110 each.
      Any suggestions or experience my fellow Lexus Users may have would be greatly appreciated.
    • Nav Radio - Control Panel Illumination
      By galtom
      got big problem.
      Got US RX300 with radio without navigation (blue display).
      I bought second hand radio form same generation RX300 from EU/UK (right hand drive).
      Radio has been changed and everything is working but one thing.
      Buttons on radio (audio, air con, etc.) are not illuminated.
      When I turn on lights all buttons should lit up (everything else still lit up as it used to) but not those buttons/controls.
      I believe all LED's/blubs are ok. It looks like there is one wire missing somewhere... Unfortunately I do not see a wire responsible for this function on any diagrams I have (radio/air con/navi/etc.).
      Does anyone have any idea where I might find and info how radio unit is lit up???
      Please help!