I had the head gasket replaced during the re-call period some 120k miles ago but I figure it must be time again. I was wondering if it's possible to leak into the cylinders. I kept looking at the oil to see if anything is getting there but nothing has appeared. I traveled approx. 300 miles today and I had to top off the radiator (roughly 1/2 gallon) about 150 miles into the trip. I noticed about a week ago that the engine was missing at idle speed so I'm figuring maybe too much water is getting to the plugs. This really sucks! All in all this has been a great vehicle and I do not run'em lightly. By the way, that testes thing....it hurts like the dickens.