First post and thought I could use some help with my car. I have an 04 gs300 with 150k miles. I'm having rough idling and vibrations when coming to a stop where it fluctuates between 300 and 600 rpm but once start going again the car acts fine. The problem gets worse if I have the ac on. The problem started off only once and a while but now its constant every time I stop. Also last night When driving home I lost my throttle response, id have to floor it then it kicks in at 5k. I've cleaned the maf so far and am looking for any other help or suggestions.

 

Sounds like 2 separate issues. The throttle problem could be a TPS or APPS issue. The rough idle could be a small vacuum leak.

 

I think you should clean the throttle body first, it the cheapest way with the throttle body cleaner, any one can shine on this?

 

Could help the idle, dont think it would help the flooring and not kicking in till 5k

 

Check for air leaks, check your harmonic balance for delamination.

 

So here is a short video of my low idle