Are they? I have never heard of this and I've mucked around with heaps of them.

Agreed.

And even with the flasher, they say if it fails, reflash it. Never heard of one killing an ECU before.

i didnt try hot water maybe that was worth a try to late now already sent it, i couldnt re-flash it as i couldnt connect to the pcm at all, ford couldnt either, they did a continuity check from the port under the dash to the pcm and all was ok,
@XTT909 what sort of internal connection problems have you heard of? would the car just die while drivin if it was an internal connection problem.

yes would die while driving mainly in winter or early morning when cold bad soldering joints internally on quite a few have replaced about 10 in 2 years with this problem

just been talkin to rob herrod, he has tested the pcm and seems good, he can talk to the pcm and has changed it back to stock settings thru the flash tuner, he's going to keep testing it and see if anythin odd comes up, he has come across this problem before in a few xr6t's and it was just a dodgy pcm, will let ya's know how i get on.

got info back on pcm, rob herrod has tested it and cant find a problem, he's returned pcm to stock and loaded the program continuiously for a full day, cant find a problem. i got the pcm back and put in car and still have same problem, an error came up on flash tuner when it tried to connect to pcm, it said: error 1018...just google it and found this:
What does the Error: '1018 Read Strategy Failed' mean?

Solution
1018: Read Strategy Failed
Unable to upload strategy tune file.

Solution:
If the vehicle has a Roush, Saleen, or Ford Racing flash on the computer. It will need to be custom tuned by one of our custom tuning Dealers.

Security system (immobiliser) working ok? the ECU is locked unless the ignition key is in the On position, and the immobiliser unlocks the ECU.

As I said before (and confirmed by Herrod), the ECU is fine, you've got some other problem.

- Check for blown fuses (sometime you can't see them, use a multimeter/test light)
- does the security light flash appropriately when the key is turned to on, light on for a few seconds then off. if it flashes or doesn't turn on at all, you've got problems there.