Transmission will pop back into park when I put it in either drive or reverse. Sometimes it will remain in drive but lunge into gear. It is not engaging properly. This is an intermittent problem.
My car has 90000 miles.
My car has an automatic transmission.
Your car has an electronically controlled transmission. The strange behavior may be due to a bad switch on the column, or there may be some reason why the program doesn’t want it to shift into Drive or Reverse. Maybe it’s as simple as a bad brake light switch that makes the car think you don’t have your foot on the brake. Whatever the problem, there is probably a code stored to help point to it. A full scan of the car with the appropriate equipment can probably uncover the fault. To have this done you can contact Your Mechanic. they will send a technician out to your home or office to check out your recalcitrant transmission and let you know what it will take to fix it.