I have been trying to figure out an unrelated idle issue, and put my hand behind the exhaust pipe. (The car was fully warmed and had been driven several miles prior.) My hand seemed to quickly feel like it was moist / damp.

I did the same procedure to a friends car right after that and I didn't get nearly the same moisture effect.

What, if anything, would this indicate?

 

water is a by-product of combustion...

 

good combustion will produce water.

 

The thing that throws me off is there seems to be more moisture in my exhaust than in other car's exhaust...

 

did you use your air?