My car has been doing this off and on for the past few months, nothing on a regular basis. Seems it happens when the car has been running for awhile and the outside temps are higher.. 80+. From my previous experience its the start of coil problems yet no codes have been stored. I am at 96k miles and plan to utilize the 100k extension on the coils before that expires.
*On a side note a co-worker of mine had a '05 T-Bird which she just got rid of. She said it was the most problematic car she has ever owned and i dont question that at all. With a monthly payment of $450 i could afford a different newer high end car and be done with the LS, the only hold back is the piss poor value the LS has, that and i have 96k miles on a '05 car. I just washed and detailed the car and it looks great but certain things about the LS just make me wish i could move on. Anyone who would give me what i owe on it the car would be gone. On the flipside my wife's '01 Dodge Intrepid is at 106k miles and still going strong, for as bad of a rap that Dodge gets i think i have gotten my money's worth and then some.