Where Is The Fuel?

[rudecuban]

Hi everyone, i am new here and hope one of you gurus can help.

I have a 2000 ES300 with 93,000mi on it. recently while driving i had a cel and trac off light come on. i have had to the code read which was P0171 . I have read thru this forum on this issue and have tried all the tricks that people have recomended, yesterday i took it to the shop and they hooked up the computer and said it was running fine, could not find problem. The problem i am having is when you really step on it , like when passing , the car has no power and is sucking air. While normal driving up to about 3/4 throttle it is fine ,but if it is pushed past this it is like a dog on a sunny afternoon. after i left the shop and was on the highway, guess what? cel and trac off was back on. i called back to the shop and they said to try changing the fuel filter and run some injector cleaner thru system. I have done this but still have same problem. The shop also said the fuel pressure was good until 3/4 throttle and than it starts to drop off, which is why they recomended changing filter. Any ideas on where to go from here?Any help will be greatly appreciated. The nearest lexus shop is over 100 miles away and i hate to drive there and have them tell me what i already know , it is running to lean. What i would like to know is why? Thank you in advance for anyone willing to help me. Todd

[mehullica]

Your airflow meter is bad. Common on this year/model. Look at the top of the sensor. You'll see a wet coating with dust/dirt stuck to it. The silicone circuit gel on the sensor leaks out on contaminates the sensor. The new sensor part number ends in 07010.

[rudecuban]

Your airflow meter is bad. Common on this year/model. Look at the top of the sensor. You'll see a wet coating with dust/dirt stuck to it. The silicone circuit gel on the sensor leaks out on contaminates the sensor. The new sensor part number ends in 07010.

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Thanks for the quick reply mehullica,

When you say air flow meter are you refering to the mass air flow sensor? If so this was supposedly cleaned and checked. if you are not refering to the mass air flow sensor, could you give me a idea where this animal is located. i have looked in my service book that i have and i cant find a airflow meter. Thanks Todd

[ArmyofOne]

Your airflow meter is bad. Common on this year/model. Look at the top of the sensor. You'll see a wet coating with dust/dirt stuck to it. The silicone circuit gel on the sensor leaks out on contaminates the sensor. The new sensor part number ends in 07010.

←

Thanks for the quick reply mehullica,

When you say air flow meter are you refering to the mass air flow sensor? If so this was supposedly cleaned and checked. if you are not refering to the mass air flow sensor, could you give me a idea where this animal is located. i have looked in my service book that i have and i cant find a airflow meter. Thanks Todd

←

yes, the mass airflow sensor.

[rudecuban]

Thanks guys for the replies. I was reading somewhere in this forum that a guy said to clean the wires off inside of the MAF with rubbing alcohol. While i have sprayed this area with cleaner is was recommended that using a q-tip and alcohol would be better . It is like night and day, i didnt see any crud on the q-tip so i thought yeah right . It worked like a dream, my hat goes out to all you knowledge people helping each other, what a great site, hopefully i will be able to help someone out as well,Thanks Todd

[SKperformance]

WHOA

who the hell ever said their is a common problem with a maf being bad ?????????

This is news to me, if it is dirty then it is dirty , don;t go making blanket statments which are misleading.

It is an engine they get dirty it doesn't mean you dispose of the $700 part.

P0171 system too lean BANK 1

First how could you diagnosis a maf being a problem when only 1 bank of cylinders are running lean and not both since the maf flows air to both banks throught the manifold????

1.you know it is the rear cylinders

2.lean = excess heat =not enough gas to the air fuel ratio

3. it is firing so it is not spark related.

4.so what is left

5.a plugged or malfunction injector ?

the shop saying it seems low at higher rpms can mean alot but it depends if it seems low to lower rpms or to the factory manuals specs , 2 very different answers.

Start with a motorvac.

While cleaning your maf is not a bad thing ,it is a really illogical answer to this problem

[mehullica]

It's news to you because you are not a Lexus technician. PO171 is FUEL SYSTEM LEAN. Not bank 1 or bank 2. BOTH banks are lean. I have seen HUNDREDS of these MAF's fail. I have worked for Lexus as a technician for 14 years. The MAF on this car fails. Period. That's why Lexus changed the design of the part, hence a new part number. They fail on the low end of the parameter. Idle should be 3.30-4.0 gm/sec of airflow. 2500 rpm's should be 12.9-14.0 gm/sec of airflow. When the sensor fails it falls .5 gm/sec under the minimum reading. Too close to the normal parameters for the ECM to isolate the REAL problem. That's why it throws a PO171 code, not a MAF code. The MAF does not cost $700.00. It's more like $200.00. Dear SKPERFORMANCE, you are illogical in making blanket statments about things you don't know the first thing about. Who told you 171 is Bank 1? Who told you the MAF costs $700.00? Get your facts straight. My advice fixed this problem RUDECUBAN had. I know what I'm talking about. I deal with Lexus vehicles every day. If anyone is making misleading statements in this forum, it's you SKPERFORMANCE

[SKperformance]

It is written in the LEXUS service manual as below

dtc no.... p0171

detetion item....system too lean(fuel trim)

diagnostic trouble code detecting condition....... when the air fuel ratio feedback is stable after engine warming up, the fuel trim is considerably in error on the rich side. (2 trip detection logic)

p0174 would be babk 2 being too lean.

[rudecuban]

Why is everyone getting their nose bent out of shape? I did'nt hear anyone making blanket statements about anything, just someone making a suggestion,and offering opinions. This is the piece that i found that happened to fix my problem "Lex-us01

post Dec 15 2004, 02:58 PM

Post #19

New Club Member

*

Group: Members

Posts: 7

Joined: 22-October 04

Member No.: 13,610

Car Model:2001 IS300 & 2001 RX300

Location:Durham, NC

Hello all, I finally FIXED this problem with my '01 IS300. Steve@Lextasy was right, but I have more to add. After some research I found a link that hit the "spot"

1. See this website for the offical RCA:

*Note: I used rubbing alcohol on a Q-Tip, becareful!

http://www.lexusownersclub.co.uk/knowledge...ex_v2&id=50&c=9

2. Like Steve suggested, reset your ECU by disconnecting the battery for 30 mins.

3. Drive the *BLEEP* out of it, once the above is done. As for my '01 IS300

it NOW performs like a new car...wowo! I'm in love with my ride all over again!

4. Then smile!!!!!!

And guess what IT WORKED !!! and i am damn grateful for the help, it saved me alot of money,and alot of wasted time going back and forth to the shop. Again thanks for the help,and info. The Rudecuban.