Could be a crack in one of the power pack tops , spark plug wire or wires. Just a couple of things that you didn't check
I have 1998 a Lincoln town car with the same problem.. It idles rough when you start, then smooths out once it warms up and you give it gas. From what I am reading its either an oxygen sensor or you have vacume leak in one of your hoses by the manifold.
sand paper
abrasive means to smooth out a rough surface
Have vehicle scanned to determine the problem
Is this when in idle? Perhaps you need to replace your spark plugs, maybe if it is fuel injected, you may need to clean the fuel system.
It is possible for a 1993 Lincoln Town Car to run rough when it is cold because the choke is in the on position. This is normal on some cars.
sounds like a vacuum leak
Starts hard then it rough idles for a short time then smooths out but when you give it gas it miss fires and bucks and does not smooth out.
Not likely but possible. I would suspect a leaking vacuum hose.
yes it is possible
Does it have a Carb.? Choke sticking and running rich could be your throttle posioning sencer is starting to go drive safe
It is possible. Replace the filter and see if the symptoms disappear.