2008 GS460. 100K miles

I have noticed when I accelerate on a entrance ramp to the highway I notice the RPM meter jerks a little like it's trying to suck for gas or something else. I can feel it in the car too. This is the only time I have noticed this. I have replaced the spark plugs about 5K miles ago.
I did bring it into the dealership a few months ago to get the fuel pump replaced as I noticed a hissing noise under the drivers side read door. They said fuel pumps rarely go bad on the Lexus. The mechanic did some fuel pressure tests and said everything looks good. He also said noise is the return line back to the pump.

Any thoughts or suggestions on the acceleration issue?

 

Check out this thread, it sounds very similar to your issue.

https://www.clublexus.com/forums/ls4...-of-power.html

 

Like the thread islandbeef posted, I was going to suggest the following:
-Disconnect battery for 10 min or so.
-Replace air filter.
-Clean MAFS - This fixed a similar issue on my SC400.
-Have your TPS checked.
-Check TB for any buildup.

Best of luck! Let us know what you find out.

 

Thanks. I did read the other thread and going to do all these steps.

Is there a DIY on cleaning the MAF and TB? What cleaner is suggested to use on the MAF and TB?

 

Uh these cars have returnless fuel systems.

 

I have noticed an improvement after doing the following steps.

- Disconnect battery for 30 minutes
- Replacing the MAF sensor
- Replaced air filter.
- Cleaning throttle body. Small black build up.

 

nice. I just saw this, but you can buy throttle body cleaner at any auto parts store. Also MAF cleaner or use electrical cleaner, both at auto parts store.

 

Do you know if the car had the valve spring recall done? It sounds like the car is pulling timing which is what happened to many LS engines which the GS460 obviously shares the engine with.

-Joe