When driving the car, after a short while it starts jerking and cuts out!

could be maf sensor

car needs to be ck'd out by a mech as to aleast scope it to determine cause

I agree this needs to be check by a knowledgable tech and test should be done, right now you and the repair person are starting to ring up a hefty parts exchanging bill, gosh all of this work and the vehicle is still doing the same thing, so try a different method, and different person helping you, may need dealership experience or knowledgable tech

the ignition coil will loose resistant when she warms up check when cold and then hot.

possible ignition issue. review when last tuned. it may be due. you need to change ignition cables so consider upgrade to a performance type(more conductivity) and a lot of times more cost effective than OEM replacements.