What do plugs tell you?
 

Any comments on these that came out of my new 94 940 na with 125K miles. they were about .045 and the car was running fine

Kind of hard to see, but they look okay....

http://www.aa1car.com/library/reading_spark_plugs.jpg
http://www.aa1car.com/library/reading_spark_plugs.jpg

thanks, that's the chart I was looking for.... you always have excellent resources

Ha...

That plug looks normal to me.

For me, it looks a bit black with carbon. It should be brown, IMO. Could drop a number (go one hotter) on the plugs and see how it turns out.

I thought that too and I was having an issue with a slight knock at high speed and seafoam didn't do much so I increased the gas octane rating and it went away. The owners manual says the ideal gas is 91 octane with 87 as the lowest so I'm guessing decades of cheap gas left a legacy for me to fix. I'll waterboard the car this weekend and see what come out the tailpipe. Then maybe I can go back to regular gas.

BTW I run my antique 289 Mustang on 25% race gas (110 octane w/ 4 grams lead) which really works well and even at $10 a gallon is still fraction the price of the one pint additives, but I understand the lead would kill the cat in new cars.

The black deposits are likely oil. On a redblock, probably valve stem seals when sitting overnight. The plug seems to be heating up and burning them off pretty well, so I would leave them alone.

Regards, Andrew.