jbdvm1988

my 2006 GX has 95000 miles and recently i've noticed a slight hesitation followed by a slight surge in speed while driving at a constant speed. it almost feels like i'm pushing the accelerator then releasing it. its a very mild difference but i'm guessing tranny and have 5k left on my warranty. any thoughts. it occurs at a variety of different speeds but most noticeable at about 35-40mph and up around 55mph.

mann777

You can do the following which will bring a huge change in your Acceleration Hesitation issues, and Engine Response.
Have the following bought.
1. Air Filter
2. CRC Air Flow Sensor Cleaner ( Schuks - $6) ( to remove deposits
3. Valvoline SynPower Carb, Choke, and Throttle Body cleaner [$4 from Schuck's]

Thats it. As you have 95k miles, it will be ideal to do with the Air / Oil Filter Change
Synopsis:
OVERVIEW
Why: to remove deposits on the MAF sensor, and carbon deposits on the throttle body that rob the car of fuel economy, power, throttle response, and idle smoothness
Air Filter - P/N 17801-50040 ( Sewell )
Ventilation Valve - 12204-50030 ($8.64) Sewell
Cost: $10 in parts [CRC MAF cleaner ($6)
Valvoline Carb, Choke, & Throttle body cleaner ($4)]
Required Time: 30-45 minutes. One of the easiest task to do if you are a Grease Monkey.
Result: smoother idle while in gear and parked, better fuel economy, and more immediate, instant throttle response.
Important Note:- BEFORE YOU START--ALWAYS DISCONNECT THE BATTERY, AND IF THE ENGINE IS HOT, ALLOW IT TO COOL DOWN BY REMOVING THE ENGINE COVER OVERHEAD WITH THREE BOLTS.
Start with the MAF Sensor Cleaning,( pretty important dont touch anythin within those sensors and they break away. and then have the Air Filter Replaced then target the Throttle Body and then replace the Ventilation Valve.
cheers

jugdish

being mechanically retarded, is this something we can have done at either a lexus dealer or a mechanic, and will they know what we are talking about?

mbenz80

When I took my engine apart at 256K miles to replace the heads, carbon deposit was excessive in intake manifold. I used MEK (methyl ethyl ketone) to clean (wash) it off. Same goes for the throttle body.
Later, when I had the previous owner take it for spin, he could feel smoother idle and a lot better throttle respond right a way. He was the one that put 210K miles on the clock in less than 6 years of ownership.
All sensors are still original (oxygen, knock, maf), engine is running "sweet" and transmission is shifting perfect.

aljodoro

Thanks so much.

Two questions:
1. Where is the maf sensor located in the GX470
2. There seems to be some discussion on the cleaner to use. Specifically not to use some of the commercial MAF sensors.

Here is a post from an earlier formum posting
-
Yes you are right the MAF type in Lexus is equipped with Karman type Mass Air Flow Sensor, which uses a moveable mirror and transistor to measure the Air Flow wake within and the trasmittor sends signals to the ECM to adjust the air flow appropriate the idle speed required. I have heard the best is to Spray 99% pure isopropyl alcohol (available at electronic stores) onto the wires to clean and shake dry. Be careful not to use other solvents as they may damage the sensor. The MAF sensor also incorporates the intake ambient air temperature sensor so it’s a good time to also give that a quick wipe with cotton which is soaked in the above liquid air spray.
__________________
I see you are recommending the CRC cleaner. Are you on the isoproply or CRC side? Looks like the CRC but want to make sure. Your advice is always so welcome. Thanks

BurgBoxstr

The MAf is on the intake tube just aft of the air filter on GX. You'll see it pretty much plain as day - held in w/ 2 Phillips-head screws.

CRC MAF cleaner is the right choice. Discussion most often seen regarding MAF cleaning is if generic Electronic cleaner is OK to use or not. To which I say get the MAF version as you can always use MAF cleaner on other electronics but I wouldn't trust regular electronic cleaners on MAF (film residue possibility). The potential to save < $10 (on cleaner) is greatly exceeded by the replacement cost of a MAF - a couple hundred $$...

Good luck

aljodoro

great help on this forum