I Have brought the Used Vehicle (2009 Toyota Camry LE) around a month ago(114 k Mileage), But upon driving i see smooth acceleration and Smooth gas pedal Push for few miles(Around 7) and upon Driving further (>10 miles) at one stretch, i sense the gas pedal is little hard to push and engine is having rough acceleration, and i am getting feet pain, as i have to Keep more pressure on the gas pedal towards sustaining the momentum of speed while on high way(No light indicators on Dash Board), Mileage not crossing 20 miles per gallon, combined High way and city roads.

I have shown to Toyota dealer who suggested throttle body cleaning and fuel injector cleaning, i had the throttle body cleaning done and for fuel Injector cleaning, i put the fuel injector cleaning liquid, but no use (Though i am not thinking this as the root cause), the

i even changed the gas pedal, if that was the issue with spring, but no change, i had the Sham removed too from pedal.

I have cleaned up the mass airflow sensor & air filter checked as being clean.

I would Appreciate if you can suggest me some direction.

If it has an accelerator cable, replace the cable. If it has drive by wire, replace the accelerator pedal sensor assembly

I have changed the Accelarator pedal sensor assembly too, No change after that too.

Can you suggest me some options to trace the issue

In 2015 my 1998 RAV4 gas pedal was sticking something crazy. I cleaned the Throttle Body using $8.63 CRC Throttle Body Cleaner fluid spray w/ old toothbrush & rags. Accelerator working great after that treatment ever since.

Vinny33a Did you perform that Throttle Body cleaning yourself? If a shop did it, is there any real way to "prove" the job was done actually? Nope. For $12 you could clean the T.B.yourself thoroughly. You'd only be out $12 and 20-30-min. Might work though.