Let me guess, you usually see nice "power boost" around 3500RPM? Then, after the car warms up, this "boost" drops off and the car struggles past 3500RPM?
Mmmm... Don't you LOVE that awesome IMRC?!?!?!?!
IMRC getting hot, causing secondaries to stop functioning. Allow it to cool down, and they work (but temporarily).
Fix?
1. Replace faulty transistor inside IMRC with good one.
2. Buy new IMRC from Ford and hope it's a good one.
In case you are wondering, this is a known issue.
