1999 Chrysler 300 poor accerleration

Have the fuel pressure check, the throttle position and MAP sensors-checked out

It's possible that you're having some transmission problems. If the "check engine" light or "service engine soon" light is on, have the codes checked first. The reason I say the transmission is it could be not downshifting all the way to low gear when you come to a complete start. Once you start moving, something may trigger the PCM to shift into low gear and off you go. You also could have a problem with your TPS (throttle position sensor). The PCM relies on this sensor to tell it that you are pushing the gas pedal. It then adjusts the pulsewidth on the injectors, among other things to give you the maximum performance under those driving conditions. Again, check for codes and hopefully you'll at least get pointed in the right direction.