Owners Forums for Ford and Volkswagen MPVs / SUVs

I have several really annoying problems which my local garage is struggling to understand. They may all be related or not - Can anyone help please?
1. The SatNav/Climate control/Radio panel sometimes completely dies. A day or so later it suddenly springs back to life and requires the radio security to be entered indicating it was due to power being disrupted. Checked the fuse box and no loose fuses,
2.When you accelerate it seems to take quite a long time for the engine revs to die down again when releasing the accelerator. (Garage seems to think this is a faulty clutch switch for start/stop control although my car does not have this)!
3. The most annoying of all - intermittently the temperature gauge goes hard off-scale and the engine doesn't seem to want to rev up when pressing the accelerator (I think this may be called limp mode!). After a couple of minutes and with the clutch depressed or in neutral, the temperature gauge goes back to normal as does the engine. There is no sign of engine overheating at all. There are no error codes generated by the OBD when any of these things happen.
Can U help please......

what codes does the on board diag come up with?

have you tried disconnecting the battery MAKE SURE YOU HAVE ANY RADIO CODES allowing for everything to power down,maybe for about 1hr?
reconnect battery,take it for a run then check for errors.

Update on my problem....
After reading the suggestions, I took my car to Halfords to have the battery checked and their little battery diagnostic tool showed that there was a lot of "noise" on the line so I changed the battery anyway although it showed no other signs of malfunction. At the same time I checked the coolant level and found it to be low so I topped up with antifreeze.

On the way back home from Halfords (about 3 miles), the car worked normally. This morning it did exactly the same thing again. However, now I have found how to duplicate the problem at will! If I accelerate "Rapidly" from about 30mph to about 50 mph a couple of times, the temperature gauge shoots up off-scale and the engine goes into limp mode. Depressing the clutch or putting the car in neutral and blipping the throttle a couple of time, the temperature gauge drops rapidly back down to normal and the car once again drives normally! The engine does not overheat when this happens nor does FORSCAN show any error codes!
Somebody somewhere must have experienced similar issues and have an explanation for this weird behaviour!!! I am getting to the end of my tether and worry every time I need to embark on a journey of any distance because I am losing confidence in the vehicle and do not want to be left stranded.
CAN ANYONE HELP PLEASE?

If the temperature sensor is failing, would this cause the engine to go into Limp mode?
How do I check the "Live Data" you refer to?

I'm beginning to wonder if this could be a Turbo problem - any ideas or suggestions anybody?