Need a fix for my problem: rattle and vibration when using gas

My 2012 v wagon has a problem I cannot figure out. It was purchased with 192K, and now has almost 196K. The problem, which started about 1,000 miles after purchase, is a short fast rattle that occurs when the car reaches 30ish mph and my foot is on the gas. Sometimes it happens when I let go of the gas to try to switch it to EV mode. I also recently noticed it while on cruise control on the highway. It seems that any acceleration will cause this rattle. Assuming it to be an engine-related problem, I have so far :
Cleaned EGR cooler
Cleaned EGR pipe
Replaced spark plugs
Cleaned intake manifold
Cleaned the intake on engine block as best as possible
Replaced main intake manifold gasket
Replaced EGR pipe gasket
Replaced PCV valve
Replaced tubing connected to PCV valve

What’s next?

My assumption is that it is a physical mechanical problem; something that is connected to the engine block is loose and needs to be tightened/replaced.

I am in Cambridge MA and there are enough gen III Prius and Prius v wagons for me to say that no one else seems to be having this problem, as far as I can tell with my ears when they drive by.

Any one can help troubleshoot? My next step is to go to Toyota of Watertown to get their assessment.

Anyone have any thoughts????

 

Can it be that simple??? I will try to jack the car up to determine.

 

Also wanted to add:
- Cleaned the magnetic EGR valve that sits beneath the plastic cap
- Replaced original 12V battery as it read very low

During the cleaning sessions I found:
- EGR cooler was filthy and almost a complete solid, packed full with buildup
- EGR pipe was surprisingly clean
- Intake manifold had caked on layers of buildup
- The spring loaded flap/gate (official name?) that sits between the air intake and the intake manifold had a ton of oil in it, as the intake manifold itself has a lot of oil
-spark plugs appeared to be original, were dirty and had oil on them, though the coil packs themselves were dry

Generally just dirty and appeared to have not been serviced at all.

Other hypotheses:
- The problem may be engine mounts?
- Is the hybrid battery about to call it quits?

 

Brakes are new all around, replaced by my mechanic after car was purchased.

No oil catch can installed yet. I have been reading about them, is there a decent priced one you may recommend?

Rattle is definitely acceleration related, occurring after/during foot on gas. I would be able to tell you what the rpm was if the car had a tach!

Oil seems to be ok, checked last week and it was as it should be.

 

Ugh just drove about 150mi this morning on highway and the Maintenance Required light just came on!

Confirmed that the rattle happens when using cruise control on the highway.

 

So far only expenses have been spent on my mechanic to do the brakes, and the cost for the replacement parts from the dealer. It’s only been doable as my free time outside work and family to wrench is zero $/hr!

 

Thanks for the tip, I will try to jack up the car this weekend and see if I can crawl under it. I have a feeling even with jack stands it will be a tight fit. From then hopefully I can see if I can make an assessment on the heat shields.

 

I also noticed increased vibration coming from below the hood at higher speeds, so maybe it has something to do with the engine mounting hardware?

 

Engine coolant flush. Ok another potential thing to do.

 

Ok thx good tip. Also check the coolant level before anything is done.

 

Hi yes, so the problem became so bad that I worked with the dealer whom I bought the car from, to send it to auction. It failed to sell twice. Then we decided to try and drive it to carmax, but it wouldn’t move much at all and was making a horrible terrible awful noise that we decided to leave it with the dealer, who offered to buy it back. He took it to the highest rated transmission shop in the area to diagnose it. Turns out it was a dampener between the transmission and engine that failed, and had damaged the transmission. The entire transmission was replaced with a used one with less miles, and last I heard the car is running fine. He ended up keeping it to use as a shop loaner. Parts were about $1200, and I don’t know what he paid for labor at the transmission shop, but it would have been more than I would be comfortable with paying, for a car with high mileage. I ended up losing a bunch of money on the car, and didn’t feel like a repair at that level was worthwhile, given the miles.

Not sure how common this problem is, but it is the first I have heard of it. Hope this helps.