When I first press the accelerator, there is a small push, and then no acceleration. After a short time, the car then begins accelerating. The pause gets longer the harder I initially press the accelerator.

My GS has 135k miles on it. recently replaced the harmonic balancer and radiator with aftermarket ones. I put in a K&N Air filter, replaced the spark plugs, all the belts, and the water pump. I'm going to replace the fuel filter soon to eliminate that, but otherwise I cannot for the life of me find what is causing this problem. Any thoughts or suggestions?

 

If the car accelerates fine while on cruise control, then please check the accelerator pedal position sensor. There are a few threads describing similar hesitations that were finally tracked down to faulty APPS units. Good luck!!!!

 

I never even thought of this. Thanks man I will definitely check into this and update after.

 

Also check if there is slack in your throttle cable. That will help with throttle response too

 

MAF cleaning or replacement has been done?