97 ford thunderbird help

my nephew has a 97 thunderbird that has the most bizarre problem I have seen in some time. When his low fuel light comes on his transmission will slip and sometimes not engage at all. He said if he shuts off the car and restarts is it will go, but will intermit slip until he stops that it starts over again. I’m stumped.

I can't believe that the low fuel light coming on would have anything to do with the transmission slipping. There is nothing connecting one to the other electrically. When was the last time the trans fluid was changed and is the level correct? I'll admit I'm not a transmission person but I would flush and drain the tranny and torque converter, replace the filter and add the correct fluid as a starting point. At least you won't have one unknown to deal with. Has any wiring been done such as a new radio or amp? I've seen people splice into wires thinking they were power or grounds when they were actually signal wires. Did this start to happen after something had been done to the car? It will probably be tough to get a straight answer from your nephew!