Actually I am not sure those look like Prius OEM iridium tipped plugs to me, these at 135k miles. You can see the iridium in there holding the gap
What is the manufacturer and model number of those plugs? If those are original equipment, it looks like an unusual amount of gasoline deposits had formed on the ground electrode and center electrode.
They were the original type iridium plugs. No record that they were ever changed, I'm the 2nd owner. If you look close in the pics you can see the shape of the center electrode and the little dot of iridium on the ground- or at least what is left of them. Pretty heavily worn and obviously a ton of fouling. The narrowest gap was about .050, the biggest about .060. The car was running fine, no issues. I was just going through it as it is a somewhat recent purchase. New stock replacements installed, good til 320k.
Are you burning much oil? The wear doesn't look particularly bad, not considering the miles on them. It's really just the amount of deposits that seems unusual.
I've only driven it a few thousand miles, not even an oil change other than the one I did the first day. I'm running 5w30 Valvoline Maxlife HM oil, and it has consumed maybe 2mm of oil on the dipstick so far. So, it's not really using much oil. Currently at 160k, I bought it from the original owner who was pretty good with oil changes (lots of records of those) and not much else. No idea how it was driven before me. Deposits like that often come from over use of fuel additives, perhaps the previous owner was putting something in the fuel too often. I was amazed that it was running with no issues when I took them out. Props to Toyota for a system that can obviously manage component wear without much issue.
