When I replaced spark plaugs about 2500 miles ago, I had some sludge built up on plug #1. Every few days I was checking the new one to see if everything looked ok. For the first two weeks there was no build-up. Well, I have been experiencing some new roughness after 3 400 mile RT trips and I decided to take a peek. This morning I found that the plug had the same sluge built up on it. I checked my oil (mobile1) and it went from a honey brown to a deep black over the last 800 miles or so. That'* about 2500 miles.

What I'm guessing is that I've got oil getting into that cylinder. Is that a fair conclusion to draw?

What do I do about it? It seems like it'* pretty slow to only show up sometime after a couple weeks. Is it possibly a problem with the fuel injector? If there'* no fuel to spark or not enough, it wouldn't burn any oil that'* in the cylinder and it would build up slowly like it is. Of course this is all uninformed conjecture. I need someone to step up as Matlock, I think.

But, I think I have found something that'* causing my engine to feel like a deisel. Whether this is causing my highway quaking is to be seen, but it seems l have a likely suspect.

If you have a sludge buildup it'* safe to guess that you are also suffering some mis-firing, that would cause the roughness. As far as the sludge goes I think it would be safe to say it could be oil. I'll let one of the Gearheads take a stab at whats wrong.
I think it would be prudent to stop driving the car until the issue can be resolved.

sludge on the plug is usually an oil foul, im thinkin your gettin some blow by in that cylinder,its possible that the rings on that cylinder could be goin bad... does your car ever blow white smoke out of the exhaust?

I'd have to agree with the blow-by.

Not that I can tell.

Holy intake gasket, Batman!

Ok, after a quick and dirty explanation of blow-by and oil fouls I realize that if that'* what I'm left with, I have few options short of replacing the engine. Are there things I can do to get through a few more months if it is indeed blowby induced by bad rings and/or cylinder wall leaks?

Does the Engine Restorer stuff work to repair rings or is entirely preventative?
Can I switch to a heavier/thicker weight oil like 10W40 to reduce the quantity that makes it up into the chamber? A mechanic had me switch on the car I drove in college when it had leaky valve guides if I remember right.

I'm not sure how much I trust mechanics in a bottle. It can't tell if its 'fixing' your rings, or clogging your oil passages. Until it can figure that it on its own, I'm not using it...not saying its bad though.

You should do a compression check before you write a check for a new engine, you may find its not your rings.