Replace your transmission pump or get a new transmission.
There is a redesigned transmission vent that should fix this problem.
Low transmission fluid, transmission on it's way out.
If your car shakes while accelerating check your motor mounts. Then check your transmission.
On a 2000 Mercury Sable : The automatic transaxle ( transmission ) fluid level dipstick would be near the firewall just to the drivers side of the engine ( where the transaxle is bolted to the engine )
A 2000 Mercury Sable might have a vibration at low speeds after changing the transmission fluid because of a lack of fluid or leaking fluid. Check the transmission case for leakage and check the fluid level before driving again.
i think i had the same problem in my 97 mercury sable ,,,mine turned out to be a transmission problem. .i would also check fuel filter ,,its located in the lower rear quarter panel
The 1995 Mercury Sable would have come from the factory with ( 5W-30 ) oil in the engines
stuck closed thermeostat or blown cylinder head gasket.
Replace the spark plugs and wires. Replace the fuel filter.
1999 Mercury front and humming noises can because by several things. Tire noises are the most common cause. A tire that is not wearing properly can cause a humming noise.
dead cell in the battery or something is on pulling power from the battery.
Mine did the same.it was low on transmission fluid..i would check that because I filled it back up and it was running so much better.