Like many of you I ordered mine way back...in February. Built first week of May, then spent weeks expecting it day-to-day, then finally told they were all on hold a couple weeks ago, now mine is expected in July.
Anyways, I talked to my uncle, who retired from Ford recently (getting the Z plan through him). He said they found the problem - the engine was making a chirping noise. Some cars already released had the noise, some didn't. So they're going through and fixing that on all of them. He said it's not a big deal.
Not sure if this has already been covered or if other people have heard differently, but just wanted to pass that along.
There is a TSB out for this concern, but engineering is still working on the issue. It further states there is not yet a fix for the issue and do not attempt any repairs. "Stay tuned for updates", it goes on to read ...."UNTIL A NEW SERVICE PROCEDURE AND/OR PARTS ARE AVAILABLE DO NOT ATTEMPT REPAIR. MONITOR ##### FOR UPDATES."
Personally, I heard it was a shortage of several certain parts and they were releasing the vehicles as the parts came in and were put on the cars.
don't know for sure, though.