I am switching my plugs now. I bought this car used and see it has Denso iridiums. I am using NGK iridium.. Will this effect it? Check out the difference
NGK also is an original equipment supplier to Toyota for the Prius. What is the model number of the NGK iridium spark plugs that you are installing?
That is the correct NGK plug. See the pdf in the attached link which confirms IFR5T11 is the correct NGK model. OEM Recommended NGK Spark Plug Part Number Change | PriusChat
The plugs are pre-gapped. The spec is 1.0 - 1.1 mm. I have found that the gap needs to be slightly narrowed to achieve 1.0 mm which is the spacing that I strive for.