2003 Lesabre not shifting from P to D or R

I have a 2003 Buick Lesabre, 3.8L, 54,200 miles. NO codes and no CheckEngine light on. Few months ago started to develop a slight jerk at around 25MPH so I changed the transmission fluid and filter, but no improvement. Then it started to have a delay in shifting from P in D or R, so I replaced all 4 transmission sensors, but again no improvement. Then the car started to stall and die at stop light or sometimes in the middle of the drive when slowing down, so I replaced the Crankshaft Position Sensor (CPS), I did the relearn the CPS procedure and car worked good for about a week. Now it looks that the car is back at not shifting from P to D or R unless I do the relearn CPS procedure, that being very annoying to do it every time you want to drive the car. After I do the relearn CPS procedure the car runs good with no problems but the next morning doesn’t shift again from P to D or R unless I do the relearn CPS procedure.


PLEASE HELP!!! Thank you in advance!!!