plug missing electrode, going thru coolant

hey guys. i've got a 96 SL2 that has right at 176k on it. and of course since i just got it paid off, i'm starting to have issues with it. and i'm really perturbed as to why....

it started hesitating a couple of months ago and the service engine light came on last week, i pulled trouble codes for it and found out that it was misfiring. so i changed the spark plugs last friday. since then it's been running fine until today. today it started to hesitate again, and i had to put coolant in it again.

when i pulled the plugs friday, the one closest to the drivebelt (cylinder 1, i think???) was covered and oil, and the plug right next to it was missing the electrode.

any ideas???

first you need to find the coolent leak, or at least if it is external or internal. check your oil and ATF, make sure they are not milky. pull the plugs again and inspect. see if it is oil on the plug and not fuel. if it is oil not fuel you may want to check the injectior. also a blown headgasket is possible if the coolent leak is not external, you may also want to check compression and cylinder leak down.