1993 lincoln town car shudder at low speeds

I have 1993 Lincoln town car that I just got.It ride smooth until it seem like it's warmed up or system loaded up.It starts to shudder a lil when I accelerate.It get worst longer the car is on or a/c and when I stop and go the front of the car vibrate hard.It only happens at low speeds and once I get over them It don't happen anymore.Some one told me it's my tranny but it don't smell burnt.What is it and what should I do to stop it.

Is the "CHECK ENGINE" lamp on? If so, have someone read the fault codes for you.

Sounds like it may be a misfire. Check that all of the cylinders are firing. With the engine running, pull the spark plug wire from each cylinder, one at a time. Listen for a change in engine RPM/roughness. If it changes, that cylinder is firing. Put the wire back in and go onto the next one. If you pull one and hear no change, that cylinder is not firing and needs to be investigated further.

I've had misfires without throwing the CEL, too. So don't rule it out just because the CEL is not lit.

Note: If you can access the fuel injectors, remove the electrical connector from the fuel injectors instead of the spark plug wires. The reason for this is you eliminate the possibility of getting shocked by some high voltage electricity AND it prevents raw fuel from being thrown into the cats.

my car is shudderin and pulsing also,only at low speeds. what coul be the problem