Acorns in the engine?

For the last couple of days I noticed that my engine was sometimes running a bit roughly.

Yesterday I went with my wife to the grocery store. While she shopped I stayed outside to check my 2005 Prius. I opened the hood. Acorns fell out! I looked at air filter box. There were acorns laying along the back (furthest away from me) edge. I was in a rush and wasn't thinking clearly. I brushed away a few of the nuts from the back edge of the box, then opened it. I lifted up the air filter and saw a fluffy blob of air filter material -- about the size of a golf ball -- in the bottom. I saw mouse chewing damage to the underside of the filter, but the top of the filter looked fine. I removed the fluffy blob, pressed the filter back in place, then went to put the cover back on. A few acorn pieces made it hard to get the cover back on. I brushed more debris aside and was able to get the cover back on.

I also checked the cabin air filter. There was a lot of leaf debris there, but also 2 acorns. I shook it out and reinstalled it.

While I was waiting for wife I ran the A/C because it was getting a bit hot inside. I saw the traction battery get down to 2 bars, as usual, then the engine started to charge it for a little bit.

When my wife returned to car we started on our way to the next errand. Engine was still running a bit roughly but ... I didn't think too much of it. After a mile -- or maybe 5 minutes -- I saw the red triangle of death, as well as the "turtle mode" icon. I turned onto the next side street. I tried shutting car off, then restarting. The engine sounded like it ran for maybe 10 seconds, then it stopped. I tried to recharge traction battery by shifting into drive, pressing hard on the brake, and flooring accelerator. The engine didn't rev at all!

I had just removed my ODB sensor -- and lots of other stuff -- from my car so I could vacuum it out! D'oh! Otherwise I would have been able to grab codes immediately. I tried stopping and restarting a few times. If I recall correctly, MFD shows engine recharging the traction battery but only until the engine stops after 10-15 seconds. Traction battery is now down to 1 bar.

We called for a ride home.

I wonder if acorn parts fell down past throttle as I drove away from the grocery store! Is my engine damaged? Would acorn bits be lodged somewhere? What should/shouldn't I do next?

I'm trying to plan what to do when I get back to my Prius later today. I definitely want to remove any acorns from the back edge of air filter box to make SURE that none (or no more) fall pass the throttle! I plan to bring a flashlight so I can view the MAF sensor assembly for any debris. After that, I plan to remove air filter box, remove MAF sensor assembly, clean MAF using MAF cleaner. Clean throttle & throttle body using appropriate cleaner (I think I still have some). Try to see down below the throttle body to see if there is any debris that I can try to "vacuum out".

Any other tips/suggestions? Should I not try to start the Prius (again!) at all?

Because traction battery charge is getting low, I think I should have the car towed to a dealer rather than my usual shop, so that they can recharge the traction battery if it becomes necessary. I realize that 1 bar is probably something like 30% so it's not flat -- yet! I'm trying to maximize my chances at getting the issue diagnosed/repaired soon. (It's a pain that it's a holiday in the US today!)

Help!
Bill

 

Good news everyone!

My wife drove me to my "abandoned" Prius this afternoon. The oil was mid-way up the mark so I added about 1/3 quart. I changed the stinky cabin air filter. Then I cleared remaining acorn bits and other debris from around the air filter cover. Then I opened the air filter cover and replaced the chewed filter with a new filter. Then I removed the air filter box so I could clean MAF (temperature and heater). I did a quick job of cleaning the throttle/bore which was getting a bit nasty. I also lubricated the throttle spring using silicone. I reassembled everything. Then tried to start the car. Traction battery now showed about 1/2 full -- weird, but I know that batteries can do that sort of thing. Engine didn't start. I used Torque Pro. Just one code: P3190. I decided to disconnect the 12V battery negative terminal for about 10 minutes to see if the car would re-try the engine. I reconnected the battery and tried starting car again -- and it started right up! I used the drive/brake/accelerator technique to fully charge the traction battery. I stopped and restarted a few times. With and without A/C. Everything feels fine. My wife followed me to my mechanic so I can have him check things out.