1994 Taurus with 3.8L engine code 136 and #6 cylinder misfire

Has anyone had check engine light code of 136 along with a #6 cylinder misfire? I believe that this may be either a bad O2 sensor or a vacuum leak, but am curious if anyone else has gotten these in the past. The light comes on after driving about 5 miles, and goes off every time I turn off the car. Any suggestions would be welcome.:jerking:

The diagnostic code 136 would indicate the system thinks it is lean on bank 2 (front side of the engine) which would be the bank that cylinder #6 is part on. As you mention, a vacuum leak would be a likely suspect, but it would be a vacuum leak specific to this cylinder bank (such as an intake manifold gasket or crack). Since you've narrowed it down to cylinder #6 apparently, you could also backprobe the fuel injector wiring or use a noid light to make sure the injector is getting pulse. If so, you could try swapping the injector with another cylinder to see if the misfire follows the injector or not.

-Rod