I thought I would post this in case anyone else experiences these symptoms in their future. Last Spring my water pump went out and my Mystique over heated (2.5 DOHC). I had the pump among other items replaced at a Ford Dealership which confirmed my car was back to it's original state. My Merc did stay cool... but it seemed to have lost power. It just seemed sluggish. I wasn't sure if I was hallucinating or just being paranoid... so I took the car in and had them check everything which all checked out OK.
Last week while driving to work, the car started to hesitate when on the highway and giving it a little gas. You could actually feel it sputtering. I put fuel treatment in along with super unleaded which didn't do much to correct this problem.
Not being a mechanic, I am reluctant to start taking things off my engine in fear I could really screw something up. What I did was removed the front three plugs and took a look at them... OH MY GOD!!!
I've seen bad plugs before and these where by far the worst yet. I even had a friend of mine who knows something about auto work confirm the condition of these plugs. So I removed and replaced all six along with new wires. If I can do this, anyone can!
The plugs were red on the ends from the engines temp getting extremely hot. Almost looked like rust. The top of the plug was burnt from the wires arching and the area were the spark jumps to was almost burnt completely off (on all six). It's amazing the car even was running.
The wires looked OK... but I felt better replacing both.
Now the car is back to norm and as peppy as ever.
So - if you over heat, you might want to check out your plugs.
