Cylinder 2 Misfire: Water Pump or Head Gasket?

Hey everyone. I have a 2014 Prius V Five with approximately 140,000 miles. I got a new head gasket at 135,000 miles from Gasket Masters right before summer. Unfortunately it started engine knocking again about 3 weeks ago. It happened every 3-4 days in the morning, but never spit out any lights on the dash. Nevertheless, I took it back to where I got my new head gasket and they inspected it but couldn't see anything wrong. There was no loss of coolant. They did something called a timing belt flush (not sure if thats how you say it) and said it was ready for pick up.

After picking up the car, I drove it 2 days later and the check engine light popped on. I read the code with a free code reader at Autozone and got the P261B code for failing engine water pump. As I was driving home after going to Autozone, the "check hybrid battery system" also came on and now I am not able to go over 40 mph (believe they call this limp mode?). Fortunately, since I wasn't that far from home,I turned the car off for a bit and then restarted it and made it back safely.

Thankfully, our mechanic friend used his diagnostic reader to pull the code. The failing engine water pump was indicated as P261B, and there was also the code P0302 for a cylinder 2 misfire. Before I got my new head gasket, the check engine light would turn on after the engine knocked, and code P0302 would be displayed after using a diagnostic reader to pull the code.

So now I am kinda scratching my head, did the failing water pump cause this problem, or could it be the head gasket again? Should I return to Gasket Masters since I still have warranty on the new head gasket they installed? If anyone else has any suggestions, I would really appreciate it. Cheers!

 

I forgot to mention I also got a new intake manifold installed at 135k miles, although I do not believe I have had the EGR system components cleaned. Sorry if this is a silly question, but would cleaning the EGR system components and intake manifold be something a mechanic with no experience in hybrids could do? or Should I find someone who has worked with this type of car before? I will check those links out!

 

Thanks for the advice! So this sounds like the head gasket again? I still have warranty on the head gasket for about 5,000 more miles or 6 more months, whichever comes first. Should I go back to where I got the new head gasket installed?