problem with misfire and bucking when accelerating 2000 ford taurus on 2000 Ford Taurus

I have a 2000 ford taurus 3.0 v6 flex fuel engine in it. When I go to stomp on gas, it cuts out and bucks extremely bad. It also seems to do it worse during shifting out. When it is in reverse it will get really bad and has even went dead on me. It also seems to have a miss in it. No codes are being thrown for it and check engine light does not come on. I have replaced fuel pump and fuel filter. Changed coil pack and changed plugs and plug wires. Have ran sea foam thru gas tank also. I don't know what else to try and my mechanic can't figure it out either.

3 answers 2 comments
POSS PLUG WIRE ISSUES BREAKING DOWN UNDER A LOAD. IF ITS A COIL OVER COULD BE INSULATORS BREAKING DOWN
Have mechanic perform a wire harness wiggle test, eng. running, since it is different in reverse than drive, engine movement may be your problem! Also have mounts checked.
I have had motor mounts replaced and still does it. the only thing that mechanic said the vacuum system was failing a leak test.
Ok! Good luck.
Did you ever find out what it was? I have this exact same model with the exact same problem excluding the reverse part.