weird!!!!!!!! counld be anything.
Couple years ago, i had by 87 camaro, late for work on freeway, puched that gas, took off, then nothing. all i heard was the rpm's shooting up. Car came to stop. put trans in park. Sat for a couple minutes,shifted back in2 drive, went back on my way.....But once i got outtta third and into fourth, i could accelerate, get to speed, and hold it, but couldn't speed up again with out coming to stop.
Talk about messed up lol.
But in your case......could be one of three things...... trans, electrical. or both
Good luck, i don't envy your situation.!