help!!!

I have a 94 t-bird that at this time I wish would fly the coupe. When ever I drive 40 - 50 mph my car goes in to nuetral and the tach goes 1800-2000 rpm and when you let off the accelerator it goe back into gear. It is getting worse now that it is getting warmer. I have had it to the mechanic several times (ford dealorship) but of course it won't behave that way then. Is there anyone out there that knows what could be wrong?

I think your overdrive band in your tranny is getting cooked! What happens when you are at 40-50 in 3rd ("D", not "OD"). Does the car still have that 'neutral' feeling?

If the band is cooked, you're in for a tranny rebuild or replacement.