Ques on MAF sensor,O2 sensors and Fuel Injection Service.

[trips1]

I went through the informative thread on gas mileage and appreciate everyone who contributed on that thread.

My 2001 RX300, 99Kmiles, gives me 15.5mpg in the city and 18mpg on the highways. My driving habits are mixed and i use 87Octane gas. I am located in southern california and so the weather is moderate and terrain is mix of flat and some ramps.

Anyways over the last 6 months i have cleaned my IACV, MAF and have also put the Chevron fuel injector cleaner 2 times in the gas tank. There was no improvement in the mpg for me.

Please can someone help me with these questions:
- Should i spent 40$ at oil change shops for Fuel Injection Service? Or is it useless and also can be harmful to the car?
- Can the independent shops determine if the MAF or O2 sensor is not working correctly?? Or is it something only Lexus/Toyota shops can find out. Or since my car is running fine with only slightly low mpg there should not be any issue with MAF and O2 sensors?
- Anything else that can be tried to improve the gas mileage.

Thanks again :-)

[lexus114]

Originally Posted by trips1

I went through the informative thread on gas mileage and appreciate everyone who contributed on that thread.

My 2001 RX300, 99Kmiles, gives me 15.5mpg in the city and 18mpg on the highways. My driving habits are mixed and i use 87Octane gas. I am located in southern california and so the weather is moderate and terrain is mix of flat and some ramps.

Anyways over the last 6 months i have cleaned my IACV, MAF and have also put the Chevron fuel injector cleaner 2 times in the gas tank. There was no improvement in the mpg for me.

Please can someone help me with these questions:
- Should i spent 40$ at oil change shops for Fuel Injection Service? Or is it useless and also can be harmful to the car?
- Can the independent shops determine if the MAF or O2 sensor is not working correctly?? Or is it something only Lexus/Toyota shops can find out. Or since my car is running fine with only slightly low mpg there should not be any issue with MAF and O2 sensors?
- Anything else that can be tried to improve the gas mileage.

Thanks again :-)

Try a couple tanks of premium fuel,and clear the ecm.Then see if the millage improves.

[trips1]

Originally Posted by lexus114

Try a couple tanks of premium fuel,and clear the ecm.Then see if the millage improves.

From the other threads what i understand is that removing the negative connection of the battery for few hours should clear the ECM. Please can someone confirm.

And any clue if fuel injection service is of any use... or it is just a simple waste of money.
Thanks again

[JohnLX300]

I had the "Fuel Injection Service" done on my RX.....I saw no improvement whats so ever. But changing over to premium for a few tanks would help. Try to use a name brand gas to. I noticed a big difference between Costco gas and Shell gas. The car fells like Costco 93 = Shell 87, and Shell 93......its my RX on crack gas!!!!

[tromly]

Shell gas is certainly the best, I no longer run on regular ever, just the midgrade, my milage is 20 city, 28 highway, both my RX's are 2004 models. Good Luck

[lexus114]

Originally Posted by tromly

Shell gas is certainly the best, I no longer run on regular ever, just the midgrade, my milage is 20 city, 28 highway, both my RX's are 2004 models. Good Luck

They must be FWD right?? (to get that kind of millage)

[Lexmex]

Originally Posted by trips1

I went through the informative thread on gas mileage and appreciate everyone who contributed on that thread.

My 2001 RX300, 99Kmiles, gives me 15.5mpg in the city and 18mpg on the highways. My driving habits are mixed and i use 87Octane gas. I am located in southern california and so the weather is moderate and terrain is mix of flat and some ramps.

Anyways over the last 6 months i have cleaned my IACV, MAF and have also put the Chevron fuel injector cleaner 2 times in the gas tank. There was no improvement in the mpg for me.

Please can someone help me with these questions:
- Should i spent 40$ at oil change shops for Fuel Injection Service? Or is it useless and also can be harmful to the car?
- Can the independent shops determine if the MAF or O2 sensor is not working correctly?? Or is it something only Lexus/Toyota shops can find out. Or since my car is running fine with only slightly low mpg there should not be any issue with MAF and O2 sensors?
- Anything else that can be tried to improve the gas mileage.

Thanks again :-)

Avoid the fuel injection service. If you like fuel injector cleaners, get something like Redline Fuel System Cleaner (Pep Boys), Lucas Oil's injector cleaner (most auto shops) or even Amsoil's PI cleaner (online for the most part). Techron is nice, and I still use it (since I use Chevron for the most part as my gasoline), but the other stuff is better.

On checking the O2 sensors (I doubt it's the MAF), the sensors can get degraded over time, but a CEL should still pop up, but it can be checked with certain more advanced OBD2 scanners. There's a load of them on ebay I see for under $100 that can do this (I plan on getting one myself soon). Mechanics should have these things (at least a reader), but the more advanced ones in stores cost $150+, and not every mechanic has one of those.

Check your tire pressure, do try Premium gasoline, check your air filter.

On gasolines, there are 3 I like (though I do experiment from time to time with other gasolines): Chevron, Sunoco and Texaco. Sunoco has given me the best MPG (but there's not a station readily close by), but with Chevron and Texaco, the vehicle runs its smoothest and I have less or no CELs unlike other gasolines I have run.

[lexus114]

Originally Posted by Lexmex

Avoid the fuel injection service. If you like fuel injector cleaners, get something like Redline Fuel System Cleaner (Pep Boys), Lucas Oil's injector cleaner (most auto shops) or even Amsoil's PI cleaner (online for the most part). Techron is nice, and I still use it (since I use Chevron for the most part as my gasoline), but the other stuff is better.

On checking the O2 sensors (I doubt it's the MAF), the sensors can get degraded over time, but a CEL should still pop up, but it can be checked with certain more advanced OBD2 scanners. There's a load of them on ebay I see for under $100 that can do this (I plan on getting one myself soon). Mechanics should have these things (at least a reader), but the more advanced ones in stores cost $150+, and not every mechanic has one of those.

Check your tire pressure, do try Premium gasoline, check your air filter.

On gasolines, there are 3 I like (though I do experiment from time to time with other gasolines): Chevron, Sunoco and Texaco. Sunoco has given me the best MPG (but there's not a station readily close by), but with Chevron and Texaco, the vehicle runs its smoothest and I have less or no CELs unlike other gasolines I have run.

Hey Lex,Shell owns Texaco now.

[Lexmex]

Originally Posted by lexus114

Hey Lex,Shell owns Texaco now.

Shell acquired some Texaco stations and changed them over to the Shell brand, http://driving.myfoxcharlotte.com/ne...ing/index.html

If you go to a Texaco branded station now, they run with Techron in their gasoline just like Chevron

[trips1]

Thanks to Lexmex and others.
Please can someone help me get the answer to

"From the other threads what i understand is that removing the negative connection of the battery for few hours should clear the ECM. Please can someone confirm."
And i think this would need to be done when i make switch to premium so that internal computer can re-learn stuff.

Also i will get the O2 sensor checked at some independent shop. The only thing is that over the years auto repair industry has made me so paranoid that i don't want to believe if i am told something is not working (O2 sensor is weak for e.g.).

[Lexmex]

Originally Posted by trips1

Thanks to Lexmex and others.
Please can someone help me get the answer to

"From the other threads what i understand is that removing the negative connection of the battery for few hours should clear the ECM. Please can someone confirm."
And i think this would need to be done when i make switch to premium so that internal computer can re-learn stuff.

Also i will get the O2 sensor checked at some independent shop. The only thing is that over the years auto repair industry has made me so paranoid that i don't want to believe if i am told something is not working (O2 sensor is weak for e.g.).

It's a little more immediate, but capacitors can still hold some energy in them for a short bit. 30 minutes should clear out all juice, but I have been able to just disconnect the cable for about 10 seconds and then it clears out the system. I'd disconnect both the positive and negative in this case.