i have a 93 sedan deville the other day i was leaving for work the car was not wanting to pick up speed, so i checked the fluid level was low i added some tranny fluid its still being sluggish if i drop it into 1st it will take off. also the park neutral switch popped up i cleared it could that be my problem, car will not start in neautral, any help would be grateful thank you!!

 

A NSS(Neutral Safety Switch) malfunction, or code, can cause the trans to take off in a higher gear than 1st. If the TCM sees a problem, it can basically just shut down the electronics for the trans, and it will be in a "fail-safe" mode, to prevent further damage, and allow the vehicle to be driven.
Is the car taking off in a higher gear(3rd)?
Did clearing the code work, or does the code come back immediately?
Is this a Northstar engine or not?
If the code will NOT clear, then there is a problem with the NSS. It could be as simple as unplugging it and plugging it back in. It may also just need an adjustment, but it may need to be replaced.
Do the reverse(back-up) lights come on in reverse?
Does it start in any other position, such as Drive, or Reverse?
What exactly was the code you got?