Getting Bad Gas Mileage? You May Need A New Air Fuel Ratio Sensor

one, two, three, four! Rev up your engines! It’s time for the Scotty Kilmer Channel today I’m going to show you how to fix a car
that has a bad air fuel ratio sensor on it, now most people are used to oxygen
sensors on cars that monitor the oxygen level to make the car run right, but most
modern cars, like this 2003 Honda Accord v6, use what’s called an air fuel ratio
sensor, and if you look closely at it you’ll see it has one two three four
five different wires going to it, now older cars like this 94 Celica, have an
oxygen sensor that only has one wire, as you can see down here, this oxygen sensor
just has one wire going to it and then those oxygen sensors evolved in later
years, to have four wires and a heater so they warmed up quickly, but the latest
incarnations are called air fuel ratio sensors, they have five wires in them and
they’re much more efficient at making the car run better, though as you’ll find
out soon, they’re also much more expensive to replace when they go bad, in
this case cars running poorly and has P0134 trouble code, which stands for
oxygen circuit has no activity bank 1 sensor 1, so now you got to figure out
which is bank 1 sensor 1, well bank 1 is the side of the engine that has the number
one spark plug in it, which in this case is over here by the firewall, and sensor
1 is the first one before the catalytic converter, so it’s this one right here,
and at least they didn’t change the size of the socket that fits on the sensor, so
my old oxygen sensor socket works fine for taking them off, so I just put the
socket on the sensor and turn it to loosen it, then we unplug the socket that
plugs it in, and then pull it out there it is, then make sure your new sensor
matches the old one, especially the clip so they snap in, because a lot of times
they have different sized nubs and they won’t fit in unless there right and
realize that these air fuel ratio sensors are going to be expensive, that’s
the price of modern technology, then you just stick it back in the hole and
thread it in and tighten it up with the socket and a cheater bar, and then plug
the connector in until it snaps, then start her up and take her for a spin, no more check engine light, and no more
hesitation when you floor it, so the next time your car breaks an air
fuel ratio sensor, why not replace it yourself, and remember if you’ve got any
car questions just visit the Scotty Kilmer channel.

100 thoughts on “Getting Bad Gas Mileage? You May Need A New Air Fuel Ratio Sensor

  1. Things I used in this video:
    1. Actron Scan Tool:
    2. Oxygen Sensor Socket:
    3. Breaker Bar:
    4. Ratchet and socket set:
    5. Mechanic’s Tool Set:
    6. Disposable Gloves:
    7. Common Sense
    8. Full HD Camera:
    9. My computer for editing / uploading:
    10. Video editing software:
    11. Thumbnail software:

    🛠Check out my Garage to see what I use every day and highly recommend:

    ❗️Check out the Scotty store:

    👉Follow me on Instagram for the latest news, funnies, and exclusive info / pics:

  2. Hi mrs Scotty !! Happy year 2018 !! … I got drastically a bad mileage with my Honda Accord ex v6 2007 ! From 250km for haft tank to 114 km since one week and a half !!! What wood you think it should be the possible cause ?? Thanks an advance !!! Simon🧤


  4. Hey scotty i got a question about my mercury sable 2002.
    The pedal break sinks all the way to the floor bord and ive done the break roter,pads,master cilynder,bleed them out. so what could be the problem in this case.?

  5. Hey Scotty
    Where would you start with a vehicle that gets horrible gas mileage, but runs well, and doesnt have any dash lights on?
    2007 GMC Sierra 1500 crew cab with 5.3L 2WD
    Hope you havent been away from Canada too long, cause im gonna give you kilometers…lol
    I have a 99 litre tank, i only got 274kms on my last fill up.
    If my conversion is right, 26 gallon tank, only got 170 miles…
    Ive cleaned the throttle body, MAF sensor, and air filter. Guys are telling me i should be getting about double the mileage, and i dont drive it hard either…
    I think im about 6.5 mpg
    Any ideas on where to start?

  6. I have a 2010 Venza. It got a dead O2 sensor then I replaced it with a NGK one. It clear the code and work normal. But couple months later I got poor mileage. Can using different o2 band cause it ?

  7. I like your spunk! Not even sure I need one of those in my outback 2014 but I will look for more of your videos! Love the black stingray.

  8. I have an old car called chevorlate aveo lt u-va …it would be great help if could do a video on how to change oil filter or air filter on that type of car😊

  9. Hey Scotty, great content!
    My BMW E46 with M54B30 sometimes gives me P0174 as a System Too lean (Bank 2). As I read on the internet, its because of O2 senzor.
    So I bought this Is it good one?

  10. My 2007 Toyota Sienna has great power, no issues starting and no hesitation but…. I am averaging 10mpg and I drive pretty slow too. Any ideas

  11. I need ur help . I have been dealing with the issue for almost a year. My check engine light has came on and wont go off. The codes was the o2 sensors . I replaced them . and it went off and came back on. For the cat being cloged. I tried to clean that. And ended up just buying a new one .. Had that installed . after clearing it came back on with no code and now awful fuel miles I am driving a 97 ford ranger with a 2.3 lt system . and I was getting 8-10 mpg. I have replaced the the mass air flow and cleaned the throttle body relaced all vacuum lines. Because the computer says lean . and still no codes but light is on plz help me

  12. i love your videos but i would be pissed if you worked on my car and then saw you burning rubber on one of your videos, i couldn’t believe that you did that to that old lincoln. keep up the good work but stop burning rubber, that’s what valet parking is for.

  13. Scotty, I have an 07 Dodge 6.7L truck. I had a "check engine light" come on and the dealer said it was the "Upstream O2 sensor"…They charged me $840. I looked them up on line and the sensor costs around $100 + or- But the dealer Charged me $250. Does it really take over $500 labor to change them?

  14. I have a 96 chev Silverado with the 305. does it have a air fuel ratio sensor. I'm thinking not, but it doesn't get the mileage it used to. Still runs great. What should I check to improve the mileage?

  15. My 2005cadillac Deville showed 17.9 avg mpg now reading 12.6.Range was reading 394 on a full tank now reading 196.No check engine light. NO loss of power. How do get the readings back I had What do I need to do to fix it. New plugs, wires,o2sensors, air filter, fuel filter

  16. I have no check engine light on in my 1995 toyota camry but I still manage to lose gas pretty fast.. What is the issue you think?

  17. hye there scotty i have a quick question. i own a 2003 honda fit currently at 400 000 km on mileage. i plan to change the 02 sensor soon. but after changing them do i need to tune them back ?

  18. I just bought an 07 vtec accord and the mpg is an abysmal 22 mpg on the hwy and it idles great and no warning lights and I use it for work. It's honestly going to bankrupt me in a matter of weeks with $90 fill ups.

  19. Scotty, is this something you would change after x number of miles even if you don't have a code? I should think the computer would tell you when it needs changing, no?

  20. I have a 2009 Malibu no check engine light but only averaging 20mpg, also the car hesitates when I give it hell. Any ideas? or could it be the air fuel ratio sensor. I was thinking maybe the injectors needed cleaned, the car has 170,000 miles so its been used for sure

  21. I'm getting 11-20mpg I own a v6 Accord coupe I don't have a CEL but idk if I should replace the sensor cause that's unusually bad mileage

  22. Hi sir, I have 2008 choverlot Malibu, it is spend alot of gas, so how we can to do, to make it working properly and save gas.
    Thank you

  23. ,,, generally you'll lose 3 miles per gallon,,,. But what's worse your carbon up your combustion Chambers,,,. !!!

  24. Based on your other videos as well, I take it that you're a Ford guy. I've always loved the fact that GM is reliable, durable, and easy to work on (except the s10, everything that should be a simple fix is a mechanical adventure in this truck). So I'm curious: Is there anything particular that makes Ford generally better than GM?

  25. But for my 2013 Prius II, if the air fuel ratio sensor is out, I think there will be a warning light on my driver panel.

  26. is this the same as a mass airflow sensor? I'm desperate and getting really bad MPG i cant afford on a 2016 ford taurus, I'd like to try to fix it but not sure how. I drive it like a grandma and get 14mpg freeway.

  27. I have a 2010 Nissan Altima 2.5 and I'm getting horrible gas mileage. I use the trip odometer and at 90 miles it took $13.01 to fill it back up which is roughly around 4.8 gallons of gasoline. Any suggestions?

  28. Do you not use anti-seeze compound on the threads so the next poor bastard doesn't strip something out or bust their knuckles removing it next time???

  29. Hi Scotty, I appreciate ur knowledge, I have Holden commodore VE 2008 v6, that’s give me bad fuel consumption that’s thirsty, advise me how I can manage fuel ratios

  30. Scotty Kilmer….I have a Toyota Matrix (2004) and have recently gotten HORRIBLE gas milage. 240 miles to a tank to be exact. I know that you have a Toyota matrix also. I was wondering if you had any thoughts on this before I spend a lot of money. I usually got 300-325 miles per tank and driving habits have not changed. This basically happened over night also. Didn't drive for a week and have been getting bad gas milage ever since….Thanks Scotty!!!!

  31. I have a town and country 2009 4.0 litre, a real fuel guzzler, 25.5 litres for 100 km town, Any cure for this? It’s ok for highway, 10.5 thanks for any help.
    Well, nobody can help me with this issue?

  32. Redex is great for getting better gas mileage.
    My bro was getting about 35 mpg with his motorcycle when he used to get 50mpg so he put some redex in and it went back to 50 mpg.

  33. How do we diagnose the sensor? To see if the sensor is bad,wiring or the ECM or some nature like that. I see we get the code but how is it tested with a multimeter?

  34. I have a '05 Town Car. It throws a P0193 Fuel rail sensor problem code. I bought a replacement from Rockauto but it is vacuum not electronic like my car. The Autozone near me only showed the vacuum type as an option. Is this the same dodad you are referencing on my car? The Lincoln is still getting great mileage averaging 22 so I've been resetting whenever the check engine light comes on. It's coming on probably twice a week. Repair shops want $50-90 just to check the code. Am I harming my car?

  35. I put one in my 01 v6 explorer I’m getting 24 miles per gallon now with the AC on well worth the money

  36. Hey Scotty thanks for all your jnformative videos. I have a 2007 audi a6 3.2. Has 2 wideband 5 wire o2 sensors. Can they give problems if its old cause my car has 185k on it and i never changed it. I have changed spark plugs filter gas filter map sensor since i have no MAF. No codes or anything but my milage is a little on the low side. Hope you can help me. Thanks again

  37. Scotty i need your help
    I heve 2014 silverado and on the exhaust smell a gasoline i dont have eny code i alredy clean the intake MAP sensor and the MAF and nothing still the same problem.
    And also its running poor

  38. Have'nt found one mechanic who can tell me why I'm getting only 5.74-8 mpg. They have been troubleshooting my 1989 Ford E250 with my money & usually I get; "Well that did'nt work it must be!?" I hear cha ching every time they do this to me and I've got over $22k in it now. Hard to find a good mechanic who knows his stuff anymore.

  39. O2 sensor most unneccasary replaced part ever .when a cel code is thrown for a o2 sensor it doesnt mean the sensor is bad it means its doing its job and telling you theres a fuel air mixture problem elsewere. Normally when a o2 sensor is bad it throws a low voltage code on the affected sensor…

  40. Thanks so much I was having an issue were I'd fill up my gas tank then I'd see I was getting such bad gas mileage. Fixed that sensor now it's good. Thing is I had no check engine lights or codes maybe I would if I left it longer but I fixed it as soon as I noticed thanks to the video.

  41. Hi sir i need youre help
    my car SUBARU LEGACY 3.0 h6
    Litile problum..
    This enging fuel missing.. More shaking car
    not evry time… Some time
    iam changing Six sparkplug.. And cleaning injector.
    Check sensors all. No have eny problum..
    But same problum again…….

    I dont no what i doo sir
    Please tell me the solution

  42. Hi Scotty,
    I have a Toyota Aygo 1.0 petrol . When the engine is cold it stinks like burning coal for 20 seconds or so, then it runs normal.
    I changed the pre-cat sensor and it still stinks.
    Do you think it could be the post cat sensor or the cat has failed?
    Other than the smell it runs normal and gives around 60-70 mpg.
    Many thanks .

  43. Why am I getting bad mileage when there's no Engine management light on, but the OBD2 is reading alternating RICH then LEAN? I've changed plugs, filters, had an Engine carbon clean and still get terrible MPG! Ford Focus 2009 2L petrol..

  44. I have 2009 F150 that I bought new. The EPA highway mileage rating was 19MPG but it actually got 17MPG. When the 30K mile major service was done by the dealer the actual mileage dropped to 15MPG where it has stayed ever since. The truck now has 69K miles. I avoid driving it much because of the low mileage. It has no trouble codes and my scanner shows no problems. Earlier this year I tried cleaning the mass airflow sensor after watching one of your videos but it had no affect on mileage. The computer in the car thinks it is getting 17.9MPG but I calculate the mileage after every long trip and it is actually 15MPG or less. Do you have any suggestion about what might be causing this?

  45. Hi Scott, I have a 1999 RX300 with very little kilometers on the clock ( just 100k). It shows fault P1135, P1150, and P1155. I changed the sensors but still it shows that bank 2 AF as defective. Fuel consumption is showing 3.5 km/L . Trust you could tell me where else I could check.

  46. I have many of your guidance video clips. You are a highly learned, skilful and experience mechanic. Helpful tips indeed

  47. @ScottyKilmer Scotty, even if there are no trouble codes found, is it possible that the Air Fuel ratio Sensor could still need replacing, to improve gas mileage? GOD bless and thank you!

  48. I got ls430 2003 model full ultra… my full tank gives me 200 miles only in city and 300 on highway… Can someone guide me what should I do to fix this issue…. I bought this car from auction and it was parked there for couple of months

  49. Sorry got a question My son has a 2008 Honda Accord LX-P he put gas 1 day ago almost full tank and the following day is down to half a tank and the car shakes a bit while driving

  50. I need help!! I'm getting 13-14 mpg City in my 2015 Hyundai Genesis sedan. Just got the car in February and it's killing me on gas!!

  51. Hey Scotty! Big fan of yours here 🙂 I have a question for you – I have a 2013 Toyota Prius Two with 128,000 miles on it. Got the fuel injectors cleaned, spark plugs changed and the PCV valve changed as well. However, earlier this week my car started shaking slightly at low speed (like 20 to 25 miles when I am stepping on the gas and accelerating). When the check engine light turned on, I got it checked by Toyota and it came up with a P219A Bank 1 Air/Fuel Ratio imbalance – would you say changing this sensor would help alleviate the issue? As for the location which is super important to me since I'd like to get this fixed myself – where is this located? Upstream or downstream?
    Hope to hear from you soon! Thanks!

  52. I have Altima 2014 2.5L, I get 15 km/l in highways which is great but what's weird I get 6 km/l in city !!! And I don't know why ??? Please help!

  53. I have a 2015 MKZ 4 cylinder all wheel drive and the gas mileage is absolutely awful. Is there anything I can do?????

  54. I have a question Scotty my 2009 honda civic i just got it 2 days ago my air conditioning was working and then all the sudden it started spinning out hot air I don't know why maybe the compressor is bad but what if the compressor is not bad because it was working two days ago what if there compressor is not bad could it have anything to do with fuses

  55. My bank 1 02 Sensor in my 09 COROLLA will not come out…. any tricks? And the wanna charge me 90 to replace it

  56. hey Scotty, I installed bank 1 sensor 2 and cleared the code. I got a sticker and drove for 50 miles and got the dummy light back on, but this time it's the bank 1 efficiency code p0420 so is my cat bad or did I get a bad sensor?

Leave a Reply

Your email address will not be published. Required fields are marked *