Ca maro

I've had my lt1 for about a year. I have already replaced a water pump and opti. Now the car is not wanting to shift Sometimes. Every once in a while it will not want to shift. I'll start driving and it will almost hit the rev limiter before I let off the gas slightly then it shifts. Then the same thing going from 2nd to 3rd and 3rd to 4th. It doesn't matter if the car is cold or warm. Just does it randomly. Ive also noticed that when I shift from park to drive it will jerk pretty hard going into gear. Then other times it will go into gear very smooth. I've been trying to remember to press the brake all the way to the floor when putting it in gear and it seemed to help. I have no idea what could be causing this. Anyone know what could cause it to jerk when going into gear and not wanting to shift until I let off the gas? Car has 126k miles. Other than the water pump, opti, tps,ign coil, and brake pads I have not changed anything on the car. The guy I got the car off of said the car had a "shift kit" but who knows. Can anyone give advise.

mrmint69

Have you checked the fluid level and to smell if its burnt?