CorrosiveSmoke

I have a 2000 lexus es300 at 136000miles in park or neutral I can rev the car up just fine but when I put it into gear the rpm barely creeps along even with my food to the floor, it gets a little bit better after the car is warmed up but not by much It still takes a minute for it to wind up enough rpm to start accelerating, I know it needs a couple knock sensors. I'm running some Chevron Techron Fuel System Cleaner through it now. any advice could it be the evap canister or pcv?