Musing about Spark Plugs

My 2004 wasn't speced with the Iridiums. I suspect the newer 2.7's are. That's why I'll try the stock copper Denso's this next time but I only have 65,000 miles on the Iridiums right now.

 

You will see no difference between a brand new set of Iridium plugs and a brand new set of conventional plugs in terms of performance. A spark plug is a spark plug when they are new. The difference comes with time & wear. The Iridium plugs don't erode as quickly as conventional plugs.

I can see using the exotic Iridium & Platinum plugs when you're trying to stretch the service interval as far as possible. It makes even more sense when the plugs are difficult to replace.
However, when the plugs are relatively easy to get to and you're doing the work yourself - the super expensive plugs just aren't worth it.

 

Some of the old stuff was a nightmare to change plugs on, one GM thing I remember maybe 70's Olds the rear right was a major problem because of the evaporator/heater box. I did one years ago and the old bomb had enough miles on it to have had at least 3 changes the rear one had never been changed. Dodge hemi left rear plug was under the brake booster I worked for Dodge in the 60's I was the one that all ways got that job because I had figured out how to use various extensions and dropped them in one at a time then fished them out with a magnet. There is one on a 4L Tacoma it is kind of a pain too. The interval in the 4L is 30K little soon I think but it's all about emissions and the emission warranty I'll be dammed if I going to use expensive plugs every 30K!