I have a 2003 GS300 and just bought some new NGK BKR6EIX-11 3764 Iridium IX Spark Plugs and NGK wires (TE79). I assume I can use the irridium type instead of the OEM platinum that are on it now, and the wires should be fine as well. But what about the oxygen sensors, they are pretty expensive and I'm thinking they should only be replaced if they are a problem or is there another shedule or way to tell if they should be replaced? Thanks in advance for your help.

 

Never mind lol, I used the forum search and found the DIY oxygen sensors thread. I was putting in "replace oxygen sensors" at first and came up with nothing via search but reduced the search to just oxygen sensors. I'm learning lol.

 

Good for you! oh and I dont know about the gs300 but the gs400/gs430 come with oem iridium plugs not platinum. GL