I changed the spark plugs on my 94 Integra today and as I pulled them out, I notice that one was RUSTED? The other 3 were ok. I was like WTF? Did water get in or is something something wrong with my engine.

 

I think rust can only happen with water, correct me if Im wrong. But for that to happen, I think it would have had to been exposed to water for a really long time. Obviously for this to occur it would of had to have been waterlocked. So idk, maybe it was messed up when you put it in. Weird....
gmoore

 

are you sure its not just corroded? are you sure its rust? why don't you post a pic.

 

where is it rusted?

if it's the top part of the plug, i would imagine some water slipped down past the spark plug wire seal...

i had the same thing happen to mine, original plugs taken out at 78,xxx and the were slightly rusted along the tops....

try replacing your plug wires or check the seals, try using some silicone spray to lube up the wire boots, keeps them nice and soft

 

It's on the top part of the plug. I try and see if I can borrow a digital camera and post pictures for you guys....