I have the 03' and have the same problem. At about 3500 rpm, the engine cuts-out hard, causing the entire vehicle to jump. THought I had a tranmission problem, but the tranny shop said the engine was cutting out. My mechanic had no ideas. ... looking for a new mechanic now
I serached the web and found a couple of reports of similar problems linked to a bad cam sensor and syncronizer. the pcm stops reading the cam senser over 2500 rpm So if the sensor goes bad you won't get a check engine light because it isnt being read. I haven't checked into this more but I am going to crack the Hanes manual this evening and see what I can learn.