2003 Ford Taurus Shaking

Uhh 160,000 miles no tune up? I would suspect your in need of having the throttlebody cleaned out and have the idle control motor cleaned up also. Change air filter, oil.

Also get the gas low, change fuel filter and run some seafoam through the vehicle see if that cleans it up better.

Next check for damaged vacuum lines which can cause it to shake like that. Check the spark plugs and change them and the wires if needed. Make sure you gap them properly before installing them.

Does car run good if put in park or neutral at a stop/