2010 Prius knocking with alternating codes.

Hi everyone, I’ve had similar issues with my 2010 Prius before but have always been able to repair them with minks issue. The Prius currently has roughly 174k on it so I’m aware it’s on the higher side.

Tuesday morning on the way to work my Prius began to have a bad shaking and “knocking” sound when the ICE was on and no gas wa a being applied. I read the code with an OBD 2 reader and received a P0304 code for a cylinder 4 misfire. Got it home that might and swapped coil 4 to cylinder 2 and likewise. The code remained on cylinder for (although admittedly I did not clear the code right then.) I then shifted all plugs down (ie: 2 to 3, 3 to 4) and then places a new plug in cylinder 1 as that is where cylinder 4s plug would have gone,and swapped the other 2 coils, again to no avail just to be on the safe side. I also finally cleaned and swapped all fuel injectors around.

The next day I cleaned out the intake manifold and throttle body again to no avail and the cylinder 4 code was there.(Neither were very dirty, but again just being safe.)

I did clear the code this time and after, the misfire persisted but no CEL was on but the code persisted.

Finally today, I finally broke down and cleaned the entire EGR valve and cooler. Cooler was entirely blocked. Finally got it around 85% cleared and reinstalled.

After checking and double checking that all was plugged in and connected correctly, we started the car and for about 2 minutes the knocking was entirely gone with no codes able to be read.

After a few minutes the Knocking returned again with a P0302 code. Then verified all plugs were gapped and secured and all coils. After replacing both plugs 1 and 2 and swapping coils around, restarted the car again this time with a P0300, P0301 and P0303 code.

I’m at a loss, I have no oil in coolant or vice versa, no white smoke, and no milky oil.

The migrating codes have me confused and unsure of where to go next. My next step tomorrow is to check the resistance of the fuel injectors possible.

I fully understand that at the mileage and age it could be a headgasket, but I’d appreciate any other ideas you all may have.

Thanks!

 

Yes, no issues there. Very consistently right in the middle of where it should be

 

Water pump was fine. Did a compression test today as best as possible without a tech stream and found low compression on all 4 cylinders. I think it might be the end of this cars life