Checked my plugs after 3,000miles of running .044 gap. There was distinct black carbon deposits on the outer part of the plug. Re-gapped them to .032 and reinstalled.
Car appears to be getting slightly improved gas mileage. However at the same time I upped the tire pressure from 32psi to 38psi, and the weather has been significantly warmer. So I don't know how much can be attributed to the change in plug gap.
I am waiting for the 20,000 mile mark to rotate tires and install the iridium plugs DUH guess I don't rotate the tires since that would change the final drive ratio and throw off the mileage calculations ok then just plugs. I think I will regap them for 0.044 gaps as that will provide more spark energy which is what I think I need to make it start easier and quicker.
If you had some soot on the outer parts of the plug that would indicate cooler temps closer to the cylinder head and would indicate that you probably have some carbon deposits in the combustion chamber.
Well I finally installed the iridium plugs today and I must say it it took a while to get the last one indexed properly but I lucked out with a brass washer that only took some snipping and filing to get the 4th plug right. The other three were close enough by swapping them around to get them really close - within 1/6 of a turn to perfect - towards the exhaust valves. The original plugs were all over the place on index and the #1 plug was not very tight at all. Car started right up and seems to start quicker for the three times I started it afterwards. Mileage coming back from Tiverton into headwinds was a bit higher than usual . . . 53mpg . . . I usually only get that when I really try and coast a lot more than I did on this trip. The highway trip to Fall River with a tail wind got me 47mpg which was exceptional also. Power up a rather steep long hill at 35mph in 4th gear was seemingly less of a strain than usual . . . I usually have to drop it to 3rd to make it up.
Man those plugs are way deep in the head !!!
All were gapped at 0.043" (close enough to 0.044") and the old ones were showing good color but you could see how the indexing affected the deposits on the electrodes.
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