[ChevLoRay]

I wouldn't go to the trouble of pulling a spark plug, just to see how it's burning. I don't believe you'd really get an accurate picture, if you did. That doesn't mean that you won't see something, but what if you don't? If the insulator is clean, maybe even a light tan-gray color, then fine. But, what if it is sooty? Is it the same as it was when you changed them? If so, you have a pattern of combustion within a given cylinder.

But, to arbitrarily pull a plug, or all of them, just to "see how they're burning" is a lot of trouble. If you were racing, and you wanted to know, you'd pull them. But to see how a given cylinder is doing, I've always understood that you have to go from a normal driving, or racing condition, and just shut it off. Running it after that point, will only cause the color of the insulator to change, and will not present the picture you really want to know.

There are devices on the market that would enable you to look at what is happening in the combustion chamber, but I don't see a normal person having one or access to such.

Unless mine fouls a plug, or I decide that it's time, I don't pull my spark plugs just to see what's going on.

If you're having a problem with gas fouling, or oil fouling, short of repairing the engine you have few options. If you are running a plug that is too cold, or too hot, you should be able to tell fairly easily. A cold plug will usually be more prone to gas fouling in slow speed, i.e., low RPM, conditions. Hotter plugs, which may be used by someone with a problem of oil-fouling, will continue to oil-foul, but maybe less often that with a normal heat range plug.

With gas fouling, ususally caused by a rich mixture...whether caused by a defective carburetor, too much carburetor or other incidental factors.....I don't think you can put in a different plug that will "solve" the problem. If it is oil-fouling the plugs, then the problem could be leaking valve guide oil seals, or bad rings, or worn cylinders, or a couple of other items. Using "non-foulers" may help, but it's only temporary. If you run them, you'll find that your engine is prone to ignition knock, or at least that is what I found in my case. But, that was 20+ years ago.

These comments are just quick and not all-inclusive. I don't know everything about this topic, but I have seen some of these such conditions in 40+ years of driving and some casual wrench-pulling. Oh, the Hot Rod, Car Craft and such, of years past, offered a lot of comment on such topics....pre-computer days, for sure.

Bottom line? Don't bother unless you have a problem.