I started to change the spark plugs today in my sons 98 Passport. The manual calls for Denso PK16PR11 . None of the chain auto stores carry Nippondenso so I went to the dealer. He had to look into a couple of different books to find the right plug and then brought me out an Isuzu box of with Champion plugs inside RC10PYP4. I have driven import motorcycles and cars for years and have never put anything but NGK and Denso into them. The damn things are a double platinum and cost nine #$%###$## bucks apiece. Any past experiences with this vehicle and the plugs ?