Chrysler Repair: speed-o not registering and stuck in 2nd, fuel gauge, fuel zone

Question
Almost the exact same story as one tagged with your response to Geoff - http://en.allexperts.com/q/Chrysler-Repair-807/2008/5/1999-300M-Trouble-shifting...
Only difference was that it didn't stall when coming to stop, had a 1/4 tank and when coming to a stop the fuel gauge descended into the low fuel zone and low fuel warning came on(when speeding back up the fuel gauge rose back to 1/4 tank).  All other indications the same.  Wondering what wound up being the problem.  Also, there's a link within the body of your exchange with Geoff where another person, "Kim" responded that the same thing happened to her son's car and that it wound up being a sensor... but not which one.  There's an AutoZone about a mile from here so I'll try to get it there to check the codes tomorrow but hoped there might be something I could have them check for specifically.
Thanks

Answer
Hi Scott,
The fault code readout is the best approach and will give you the most specificity. Let me know what the numbers are and we'll go from there. Also, what is the year, make, model, engine? The output speed sensor is probably involved in the limp-in mode that you have going on now.
Roland