John2GS430

Hello everyone, my name is Johnny, and I own a 2004 GS430 with just under 100,000 miles. I bought the car used in 2008 when it had 60,000 miles. When I first bought the car, I feel that it had a lot more power than it has now. It used to easily spin tires when taking off under full throttle, and these days it does not even chirp tires. I measured the car's 0 to 60 acceleration time, and it was about 7 or 8 seconds, which is a lot slower than Lexus claims.

I had a full service and tune up performed when the car reached 90,000 mile. They replaced my timing belt and water pump, spark plugs, and flushed radiator, brake and transmission fluids.

The car generally runs and drives excellent, fires right up even on the coldest mornings, idles smooth and drives great. Its just that it loss a substantial amount of power that it once had. In fact, once it gets up to speed, the acceleration is still great, possibly as good as it always was, but the initial take off under throttle is a lot worse than it once was. Is this a common problem with an easy solution?

GS4_Fiend

iTrader: (22)

Try getting a new air filter and clean the MAF first.

John2GS430

Thanks GS4_Fiend, they replaced my air filter when they serviced the car at 90,000 miles.

What is the MAF?

Rippaflow

iTrader: (4)

Mass Air Flow Sensor

mphsatty

Some have noticed substantial improvement by replacing the in-tank fuel filters (one is just a sock). Even though they're called "lifetime" filters by Lexus, it seems most people can see a big difference when changed after the 100k mile mark. Anyway, it worked for me.

clos430

iTrader: (21)

Did you use aftermarket parts ? spark plugs ? Did u notice it after the 90k service ? Also try cleaning the throttle body

John2GS430

All of the parts used for 90,000 service were factory original parts. I am going to look into the MAF sensor and fuel filters as recommended. Thanks everyone.

NEbiker10

iTrader: (1)

I just cleaned my MAF and throttle body 5min ago and notice a little quicker response. hit 75 down the main street like nothing

DryEye

did you try resetting the ECU? try unplugging the negative battery terminal or removing the ECU fuse in the fuse box for about 10 minutes or however long it takes to reset the ECU. LMK if that works.

John2GS430

I have done some research on the MAF sensor, and it seems that it is easy enough to replace it on my own. I will purchase one and replace it, and I will reset the computer while I am at it.

Cleaning throttle body seems to be quite involved and out of my comfort zone. I will have it done by the mechanics next time I take the car for service.

mphsatty

I have used a product called "Intake Snake" for a good while. It cleans your throttle body without removing it from the car. Very thorough and easy to use.

mphsatty

I forgot to say you first disconnect the intake air duct from the throttle body. Then with the tool's flexible handle, you guide the cleaning end (saturated with TB cleaning fluid) through the throttle body, especially both sides of the throttle plate.

GS4_Fiend

iTrader: (22)

Don't replace it if it's not bad. Try cleaning it with a electrical parts cleaner in spray can bottle. Dont use brake cleaner because it leaves a residue film behind. You are gonna be spray a 2 small wires. That's the hot wire element from the MAF. The other long element is the IAT sensor, you can clean that too. But to make a difference you must clean the 2 small hot wires and clean it thoroughly. Search how to clean MAF.

John2GS430

I purchased some CRL Mass Air Flow Sensor cleaner and cleaned the sensor. It was a very straight forward task, but unfortunately it did not yield any performance improvement - the car drives exactly the same as before.

It seems that a new sensor is going for around $150. Before I make the investment, I'd like to make sure that this is a common issue. There is no check engine light on the dash to indicate that this sensor is malfunctioning.

GS4_Fiend

iTrader: (22)

Did u spray the 2 small wires?