Acceleration rattle when I release gas pedal

i have searched for existing threads! I promise!!

2005 Prius 206k miles

My HV battery died in the middle of nowhere. I limp drove the car, gas pedal to the floor, up a steep hill, barely doing 8 miles per hour, got to the top, and coasted 5 miles down hill home.

Seems like I "stretched" something within the throttle system by pushing it so hard sans any HV battery.

I replaced the HV battery with some help from a great priuschat member!!! Also replaced trans oil, 3 way coolant valve, engine oil and filter. Since I've now sunk a couple bucks into my 05 Prius, I wanna keep it running another 40k mikes at least.

I've put 3500 miles on it since new HV battery.

Now, whenever I let off the gas pedal at high rpm I hear a loud rattle for a couple seconds. I cleaned the throttle spring and plate. It seems like there is "play" in the throttle spring. I'm pretty sure the rattle comes from the throttle. Any suggestions? Where is the actual cable that pushes the throttle spring when I accelerate? Don't wanna replace the whole throttle body, as likely I will be getting rid of this car within next 18 months.

Can I just replace the spring? If so, any links to a step by step?

I tried to tighten the bolt by the throttle body. It looks like it could be a tensioner? I only gave it a 3/4 turn. The quandary is... it seems like if I tighten the bolt it will only make the plate stay open??