Replaced wires, plugs, air filter, pcv valve, gas filter

That'* a very basic tune up. The coils should be checked and possibly need to be replaced if they are old. Could be the cause of your sputtering. Also, there is nothing in that list that would have corrected any transmission problem. Concentrate on the coils for now. Then lets see if the problem goes away.

10 4 how do i see if coils are good or active?

There'* a write up in tech info under testing. just look for coil test. It'* easy to do.

You thinking a possible cracked coil, Danno?

We should also have you check the plug wire routing for any pinching and to ensure the #6 plug wire isn't touching the O2 sensor.

Ya, I'm kind of thinking cracked coil. Might want to try the water mist test. Spray a mist of water on the coils, and wires when the engine is running. Do this at night and then turn off all the lights. Watch for blue flashing. Another possibility is spark plugs that have screw on tips. Some times they get loose.

You know..that'* why I no longer use NGK'*? I like the price and they are more readily available for me...but those darn screw on tips screwed me one time too many.

I'm with you on the misting. Love the arching show you get at night. For an odd reason my ESP (That'* extra special powers) thinks the #6 didn't go back into that plug wire holder on the backside of the fuel line/O2/engine cover bracket.

Another ? The impala lower rocker panels (located underneath the driver & passenger doors) are they interchangeable?

Maybe a MAF sensor?