Is this a high mileage vehicle - transmission?
I would be looking at the TV linkage from the engine to the transmission. Broken bushing, it popped out of adjustment.
If you live in the snow belt areas , this linkage can corrode , become sticky.
Unless you have engine problems and you are stepping on the throttle harder while the engine is cold
Some people are like Slinkies... Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs.