I've owned this GS 300 since '06 and have always had a slight hesitation during acceleration when hitting the gas after turning a corner or passing another car in the 20-35 mph range. It's like a dead or flat spot between the pedal and the engine. The dealer has told me this was the first year of the GS's "fly-by-wire" throttle system and this was a known issue and they don't have a fix.The car now has 105k miles on it and the problem has gotten more pronounced lately. Any ideas? Thanks.

 

Though it's not on this site, I googled what you were looking for and this guy had the same symptoms, delayed acceleration when turning, etc and he replaced his MAF and the problem went away. A temporary fix he said was seafoaming the car.

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This problem is common and actually is covered on this forum. On your throttle body there are 2 sensors as well as the Throttle Control Motor that go bad at higher mileage. One sensor is the TPS sensor in the front which if removed has to be re-calibrated by the dealership for a hefty fee. The other is in the back end of the throttle body and is your Acceleration Pedal Position Sensor (Lever Assembly Throttle Sensor) I am having the same problem on my 02 Gs300 and it is tricky to figure out which of these is the problem....they all cost around $300 new. A lot of people seem to buy a used throttle body and swap out all the sensors/motor. Im no pro so there could be more info I am missing but this is what I've gathered in the past couple months of research. Hope it helps man.

 

MAF sensor probably is not the problem. Get MAF cleaner and that will help with throttle response if anything but chances are it is not going to fix anything.

 

I just sprayed some cleaner in my MAF and it fixed my problem immediately. $8 vs. $100 to replace.

 

Hesitation problems can be anything from bad connections, bad ignition timing, MAF, TPS, air filters, spark plugs, all kinds of little small things. Just check the small things first! Like cleaning connections.