Hey guys, this is (I think) an unrelated problem to the cutting out and misfire that I think is now fixed on my 1989 560SL with just over 80,000 miles. Here is what is happening: Cold, she starts up fine, in fact, starts up fine either hot or cold. Idles fine, smoothly, and since the new plugs, rotor, cap, plug wires and coil that I installed the other day, now accelerates hard and strong just like she used to. All the filters have been replaced as well. The thing is, at idle, the fumes will run you out of the guarage, its running way too rich at idle. There is no black or white smoke, the exhaust is clean, just heavy with fumes. I have removed the advance limit resistor. I should mention now that while extremely worn, none of the plugs were fouled, and for the most part colored as good as plugs can look with what passes for gasoline nowadays. Until recently this ultra rich running was only there when warming up, but now it seems to be there hot or cold, and fuel mileage has dropped off, not a lot, but there has been a drop. The exhaust system seems to be original, along with virtually all of the injection system. I will bet good money that the coil I just changed out was the original coil. This car does not sit, I drive her daily. I use Redline fuel conditioner often as well. My gut feeling is that something is starting to fail, but what....? Before I start troubleshooting and changing out parts willy nilly, any thoughts on where to look first? Thanks again, Guys!!

First thing I would be interested in doing is checking for a cold start injector. If your car has one, try disconnecting the plug for it to see if there is an improvement. If not, it is possible it is leaking a small amount, but not as likely if it made no difference when unplugged. Also, catalytic converters don't last forever, but that shouldn't have done anything to affect gas mileage although without a properly working one, the gas fumes can get tough to breathe.

Smell of gasoline on cold AM starts can also mean the beginning of the end for the O2 sensor. If it hasn't been replaced, service cycles are 80-100K for most.

Good luck.