my 92 marquis has a problem(S)

[92 Merc]

im a newbee to the site, hopefully yall guys can help me out.....well, my grandpa passed down this car to me, its a 1992 grand marquis...the odometer reads "65,366" but according to my grandpa it stopped working 3 years ago. so im not very sure on how many miles the car actually has...well, my questions are the following............why does my car smoke when i pull out of a stop sign/ stop light? also, it shifts pretty hard....1st, 2nd, and 3rd kick it rather fast and jerk you quite some. i was told the hard shifting could be because of an old catalyc converter??? and i was told that the reason my car smokes is because of oil in 1 of the rear plugs...could yall help me out please?

-thanks..

[gasman1075]

The smokeing is oil being burned,it's being passed into the combustion chamber and being burned along with the fuel.This could be a few different things from worn valve guides to worn piston rings.
Change the oil and use a quality oil for high mileage cars.
As far as the hard shifting,the cat converter is not the place to look.These cars are notorious for the transmission range sensor going bad,this more then likely is your problem,it's a $30 part and about 20 minutes under the car on your back to change it with simple hand tools.Autozone.com had detailed instruction on line on how to change the part