High fuel consumption

Hi,

Wow! That isn't good. Does the vehicle seem to be running properly other than the fuel issue? Have you noticed any black smoke from the exhaust? Take a look through this link:

https://www.2carpros.com/articles/engine-black-smoke

Is there anything you can think of that is acting differently than it did before?

Let me know.
Joe

The car runs fine, no black smoke,there drag in the engine sometimes. I check it with OBD2 the only error mass airflow sensor permanent. I replace it with new one same error try to clear it but same. But no check engine lights.

Hi,

Can you provide the code that you found? That way I can look into it further.

Joe

Error code: P0102 Permanent Mass or Volume Air Flow Circuit Low Input.

There are a few things that can cause this. I have the diagnostic flow chart which requires a specific type of scan tool. If you look at the attached pic, it shows possible causes. If you want, I can provide the directions. However, I don't want to overwhelm you if you are not comfortable. LOL It's extensive.

Let me know if you want me to send them to you.

Joe

Here are the readings I got from the obd2 scanner I use. please can you look at it and tell me the area I need to lookout for? Please find attached of obd2 reading.

Thanks for your response.

Okay, the fuel trims indicate the computer is adding fuel to the air/fuel mixture. I noted the oxygen sensor is a .5. That is normal, but it should be fluctuating up and down between .1 and .9. Is that happening? Also, do you have the engine coolant temperature sensor's reading? That's the only one I didn't see.

Let me know.
Joe

Okay, please fine attached for the engine coolant temperature sensor reading 90c.

Thanks waiting for your response.

For the oxygen, I will check it and see if it moves between 1 to 9 and get back to you.

Hi,

The temperature (if that was operating temperature) is nearly perfect. Let me know about the O2 sensor and if there are any other symptoms you can think of that could help.

Take care,
Joe

Hi, please find attached of the OBD2 data readings,order symptoms is that when I engage on drive the engine will be vibrating at idle.

Hi,

Everything there looks normal. Have you had the chance to check the O2 sensor?

If I may, 9 times out of 10 it will be the MAF sensor due to contamination of the hot wire. At this point you are best to replace it. here is a guide to help walk you through the steps with instructions in the diagrams below to show you how on your car:

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

Check out the diagrams (below). Please let us know what happens.

Hi,yes I have change the air filter and the MAS airflow sensor. my car average MPG has come back to normal. I am now getting 21 mpg, you guys are the best.

Thanks very much I appreciate your support.

Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.

I have recently purchased a 2004 Rav4 Base 2WD, 125k miles. Recently, my gas consumption has gone way up. I am averaging 17-19 mpg city, and max for hwy is 23. I drive the car lightly, no lead-foot. When I apply the brakes, my RPM's drop to 500, the car shimmies for a 10-15 seconds then the RPM's kick back up to the 700's. I am not getting a check engine light on the dashboard, but I know for a Toyota this is not normal. Does anyone have any suggestions as to where I should start my troubleshooting? Thank you in advance for any help or suggestions.

The idling speed is erratic and such problems are usually caused by restriction ini the throttle body and IAC air passages. Getting both items cleaned should stabilise the idling speed and hopefully that resolves the higher fuel consumption as well.

What about the map or maf sensor, would that need to be cleaned as well? I just bought a Haynes manual for my car, but it won't arrive before I take a road trip. Are there pictures available to show the component locations? Thank you for any help.

The MAF is a delicate sensor which can easily be damaged and if you wish to clean it, there are special cleaners available specifically for this job. You must avoid excessive pressure/force to be directed at the sensor. It should not be subjected to shocks.

The throttle body is at end of air hose and the IAC is attached to it at bottom, with 2 coolant hoses.

http://www.google.com.my/search?sourceid=ie7&q=throttle+body+cleaning+youtube&rls=com.microsoft:en-MY:IE-Address&ie=UTF-8&oe=UTF-8&rlz=1I7ACAW_en&redir_esc=&ei=Y4L-T92cDsHamAX-7cSEBQ

Try above link.

I have a 2002 Rav-4, getting only 16 miles to the gallon in the city. Had the fuel injectors cleaned
professionally,Transmission fluid & filter changed, check for sticky brakes, no problems their. No check engine lights are on. Any idea what would cause poor gas milage?

If it is running rich, then you may have a partially clogged CAT.

Remove CAT (most Toyota's are bolt on) and inspect.

Also clean MAF.

Thanks for the info. Being a novice can you explain CAT & MAF.

CAT is the convertor in the exhaust. MAF is Mass Air Flow sensor before throttle body. It measures the volume of air entering engine.

This '97 Rav4 gets the worst gas mileage I've ever seen. It's getting around 130-150 miles per tank. That's driving very carefully, no fast stops or starts, keeping speeds 60 and under. At highway speeds you can see the gas gauge move downward.
It has no codes set. And the plugs, distributor cap, rotor, and plug wires are fairly new. All the normal things like tire air pressure has been checked.
This car has had the engine and transmission removed a couple of times because of trans issues. So it's possible that the vacuum lines have been reconnected wrong, if that is a possible cause of the poor mileage.
The engine starts and runs fine, it just drinks gas like a car with a 12 cylinder engine.
A check of the timing shows it's off by a couple degrees, but the timing can not be adjusted on this engine.
Thanks for any help you can give me.

So would a donation help get this question answered? I could use some help, I'll give what I can.

Have the timing belt checked. Ensure it has not jumped a tooth.