Engine miss/skip when warm and driving.

It is hard to give the exact cause without being able to experience the problem first hand and do some basic diagnostic tests. Ford are "bad" at setting misfire codes. You engine has one ignition coil per cylinder, I have seen the ignition coil fail intermittently and not set a code. You could first try replacing the spark plugs. With a professional grade scan tool you can view what is Mode 6 information and figure out which cylinder has a misfire.

Patrick is correct. Mode 6 will typically give us the information needed to diagnose it correctly. They is an customer satifaction program in which Ford will replace failed ignition coils. Give me your vin# and I will see if you have coverage. bglastetter1@aol.com

I had a similar issue with my '04 Tbird. Sometimes came up with a misfire code, but mostly not. When a tune-up didnt fix it, and after much frustraion, it turns out there is a service bulletin on the ignition coils, something about leaky gaskets allowing moisture in to fail the coils. Dealer should replaceme up to 10yrs/100k miles (from what I remember). Search the net for Bulletin No: CSP 07M07

Check ign. coils you are right at the mileage where they start failing. They are warr. for 100K miles and can be checked by reading computer codes.