Shifting from 1st to 3rd or Engine bogging
 

2001 Crown Vic HPP, last couple of weeks I started have an intermittent problem, now the car is doing it all the time. Start accelerating from a standstill and car seems fine up until the 1st shift. When the car shifts however, after the shift the engine rpms drop low as if the motor is bogging down or the car shifted straight to 3rd from 1st. Could be going straight into overdrive. I've turned O/D off however and the car behaves the same. This happens while gently accelerating from a stop, I drive like grandma. Is my tranny toast? Could it be a throttle positioning error, or clogged fuel filter? I don't know if the car is actually skipping 2nd or just bogging down.

What do you get if you shifted it manually from L then 2 then D ?

Don't know I'll try that and report back, thanks for the suggestion.