Missing timing alignment mark
 

So I got my idle down to a normal range, but now the car runs like crap. Really rough stumbling idle, barely any pick-up, etc. When I tried running around, eventually a CEL came on- code 1 for O2 sensor. It goes away when I turn the car off and back on (but I soaked it in brake cleaner and scrubbed it off anyway, it had some decent carbon and smelled like gas, from running rich from a maladjusted timing I'm guessing).
Anyway, I tried to adjust my idle last night and lo and behold, that lower timing cover that I'm missing is the part that has the timing alignment mark. Does anyone out there have any ideas as to somewhere else I can reference off of? I adjusted it some, and got some power back, but it still smells really rich and runs really rough.
Please help, my wife is ready to shoot me in the face for all the time I'm spending on getting this car running 'good enough'. And then she'll shoot the car.

Re: Missing timing alignment mark
 

If the O2 reads the correct resistance. Clamp it in a vice and hit the tip with a propane torch till red. It will burn the crud off the protected tip behind that hole filled sheath.
Note the voltage also when it goes red. Think about 5 volts . Could be wrong, so YouTube that