john, sounds like a bad o2 sensor and a bad brake mc.  i had my mc replaced
by volkscafe, not having the time or inclination to do it myself.

good luck!

bill

>Looking for input here. Thses are the symptoms.
>
>1) Engine related:
>a) Tailpipe coated with heavy black soot.
>b) Black soot line beginning to form upstream of muffler where Cat
>Converter attaches.
>c) When engine  is warm, with a light foot on the gas at cruise on level
>ground or going downhill, engine twitches constantly.....like an erratic
>miss.
>d) When engine warm, idles smoothly, then will suddenly just die. Also
>happens at stops.
>e) On cold starts in the morning, moderate smell of gas, eventually
>clears as engine warms
>
>Any suggestion as to how to approach this? New temp 2 sensor? New Ox
>sensor? Both? This engine has new plugs and ignition wires.
>
>Also, brake fluid leaking profusely under dash. Brake pedal requires
>constant pumping up. Bad brake master cylinder I'll bet. How tough to
>replace? Procedures?
>
>Thanks,
>
>John Rodgers
>88 GL Driver