Newbie. Need advice on buying a used prius.

I would tend to stick with OEM or at least third-party ones that the manufacturer says are for the Prius.
Your link mentions 2004 - 2007 and you have a 2009 Prius, IIRC.

 

Sorry. I guess I misread that?

 

The front of the engine and number one cylinder should be the passengers side. All cars I have ever worked on the transmission is where the rear of the engine is no matter what it's orientation is in the car.
You swapped the coil on plug and installed new plugs and the misfire stayed on number one cylinder, if this is correct how hard is it to move the fuel injectors to known good cylinders. I have never worked on this fuel injection system because my old Prius never gave me a problem. I'ts all about time versus money when troubleshooting. Go ahead with the compression test first, it's the cheapest and doesn't take long. Here is another problem I don't have an answer to is how to take a compression test on a Prius because of the way it is designed to start. If you are going to buy a compression tester I would look into a Cylinder Leak Down Tester instead but you will need an air compressor to do that and it is actually a better test. Just some thoughts.

http://www.harborfreight.com/cylinder-leak-down-tester-62595.html

 

I gonna chime in here because My car had PO300 and P0301 when I bought it. @123k mi. The first thing I did was all new plugs. Cleared codes only to have it return after 2 drive cycles. The next thing was swapping cyl1 and cyl4 Coil positions. Cleared codes. Code returned after 2 more drive cycles. The next thing I tried was Fuel injector cleaner. Cleared codes again. This time the MIL stayed off for about a week. Then returned. I tried 3-4 tank fulls with injector cleaner. Each time it would last about a week the MIL would return. Finally I decided to replace the injector on Cyl 1. You can do it without removing the rocker cover. 1 only replaced the 1 injector $ 32 from Rockauto at the time.

Cleared codes and the never returned. I’ve put another 147k Mile on it and no codes for misfires have ever returned.

Btw, replacing injector 1 or 2 is relatively easy. However with 3-4 you would likely need to remove the rocker cover. I would avoid replacing All the injectors for that reason. That’s a much more involved job. I changed the cyl 1 injector in about 20 minutes being very slow and deliberate. You need to be very diligent to get the injector fully seated within the fuel rail. Those thick O-rings are a tight fit and require a firm push to seat them.

Here is the thread I referenced when I had my problem. See post #13 for replacement details. I commented several posts later with my results.

2005 Prius P0301 misfire | PriusChat


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