I have a 2003 5.4 with 150k but its doing something after it warms up. I loose some power from stop lights and sometimes it won't drop out of OD on the freeway. Other then that it drives great and actually shifts good. I just had the trans fluid changed and it didn't help. Should I look at something else?

 

Not much to go on here. Do you have a OBD2 scanner? If not I would get one and run some tests.