1998 f150 xl 4.6. Idles fine in park and nuetral. In reverse w no throttle lugging noise. When in drive tries to stall. Once moving ok until 40 -45 miles per hour then slipping and surging. WOT takes off ok. When slowing to stop engine stalls when no forweard motion. Help.

 

are you sure it's your TC? it sounds like it could be a dirty MAF sensor or more likely a dirty or bad IAC (Idle Air Control) solenoid?