Would this give me a rough idle? I just replace a lot of things on this car, LIM gasket and all the goodies associated with that, and I am going to replace the O2 sensor tonight but I pulled the wire off of the coil and noticed this(see picture) it was the only one that was different colored. I cleaned it off and have not had a chance to drive it yet. Also, on a slightly different path, if you overfill the coolant reservoir, will it leak all over the ground? Please tell me that is my problem. When I replaced the LIM gasket, of course I drained everything, then refilled the most I could. I drove it a couple of days and filled the radiator all the way up and the reservoir to the line. It has been so crappy here in Nebraska weather wise that I have not had a chance to crawl under it to see where it is coming from. The radiator is still full, but the reservoir is low again. I do not see any leaking around the LIM gasket or anywhere up above. Any ideas are appreciated!!