Engine Knocking and shaking only when accelerating

I like the start of your post "car drives great except when the engine turns on". I hope you didn't pay a lot of money for this car.

This rattle on the 3rd Gen Prius usually caused by a bad head gasket.

 

“Hey Walt, just got off the phone with a customer. They have a blown head gasket. They want to wait and see if it gets worse”

Car Care Nut Head Gasket Borescope Test

 

Believe it or not my wife thinks changing the spark plugs is going to straighten this problem out seriously this is just how some folks think they can't help it and this person has been with me for 25 years and sitting in a chair she's the best armchair mechanic you've ever met till she stands up seriously this is no joke she's telling me that me putting in new SC16 spark plugs straightened out the death rattle and I told her I seriously doubt it. I only change the plugs so you'd be quiet nothing is fixed tomorrow or the next day It will seriously fail You should just stop driving it until you figure out a plan and use one of the '08s .. But I'm all about you letting it fail so I can get that piece of junk out of my house yard and property It is a sore subject with me and just that's that this is a Toyota epic fail I'm glad it's the only one I've had to live through with this company.

 

Strangely changing the plugs will "fix" it for a few days to a week in most cases. So give your wife a psychological win to build brownie points to buy a gen4 or hybrid pit engine for a swap.

In the meantime:

 

Yes the newer plugs with the proper gap so on and so forth Will clean it up for a minute it'll be right back in the morning by lunch time what have you. The car has 360,000 mi on it It's been in cab duty basically for the second half of its life and college duty for the first half The car really isn't in that good of shape to be dropping engines and things in it. It's got the real perforated leather that starting to peel so you have to put something over it or be wearing long pants. All the plastics inside are fading and the paint is coming off there signage that's on the plastic like the universal symbols are all disappearing so on and so forth this is normal wear and tear in a plastic car Don't get me wrong I have a generation two with leather interior the smooth type not the perforated with 213,000 mi on it sitting next to the generation 3 I don't know how anybody would walk by the two and open the door to get in the three No way in the world The two is in way better shape inside even outside other than what the 2010 is red and the '08 is silver but side by side rationally there's only one choice It's shocking how many people take to the 3. But in reality that kind of makes me happy because the Gen 2's just keep falling out of the sky for almost no money and are twice the car as far as I'm concerned so it's a win for me and that's that.