wont go from 1st to 2cd gear unless i let off the gas, or put gear shift in 1st then 2cd manually. Also overdrive light is blinking. its an automatic

Hi did you connect a scanner? and pull codes you can clear code after recording if any.try disconnecting the battery that might reset the system
you will need to check the tps sensor for glitches or drop outs if ok you headed to the transmission shop probably a solenoid problem but often they will try to sell a rebuild.

Regards