Hello, I hope the following is of assistance.
The 2 codes you need to investigate would be the glow plug code (P0380 at a guess) and fuel pressure valve (P0087, P0089 or similar).
Out of the 2 I would say the fuel pressure concern, around 90% of the time this is caused by a fuel filter concern which means the engine management can't control the fuel pressure, if the pressure goes outside the preset parameters then the engine management will reduce power to prevent any possible engine damage. When you turn the engine off and restart as the fuel pressure is OK the engine returns to normal running until the fault is detected again.
If there is a glow plug concern then this is either due to water getting into the glow plug relay or a fault with the actual glow plugs, if there is power to the glow plugs when you turn the ignition on then this suggests the relay is working OK.
The fan performance wouldn't give a lack of power, cooling fan concerns on this model are usually due to the fan control module failing, this is part of the fan and was subject to a manufacturers recall a few years ago.
The CAN fault is usually U1900 and never affects the running of the car, the code seems to be set on most Focus in error.
Start with replacing the fuel filter especially if it hasn't been changed within the last
10000 miles as I've seen many filters where they have caused problems well before the specified replacement interval.
I hope this helps, let me know if I can assist further and I'll reply as soon as I'm able to.