Hi everyone.I own a 2.0 ltr 99 bug and i'm experiencing the following : recently the blue coolant temp light would come back on and flash. I researched this and was told it was probably a faulty coolant temp sensor. I ran like this for a few weeks and the light stopped coming back on and worked as it should, going out when the engine warmed up. At the same time as this i noticed the idle was not as smooth as usual with the occasional hesitation on accelleration and a strong emission/gas smell which is getting worse. I replaced the coolant sensor today and as the engine was running i checked the exhaust and noticed a black residue on the road which had been chucking out the exhaust.thanks for any info.