while driving I found no response when I press the accelerator pedal the car slowed down and I pulled over. Turned ignition car started. this happened three times in 3 miles. I then stopped for ten minutes and when I tried to start the engine the engine did not turn over all I heard was a click every time I turned the ignition Key. I got the Jump leads out and tried to Jump it off another car. Would not start just clicking. It was raining at the time so I decided to look at it the next day. When I switched on the next day it came up with a message, "now in economy mode" Turned the key and car started and drove home . Has any one any Ideas this is not the first time

Graham, July 2019

Thanks for responding
I looked on my OBD2 and No codes. My car is a citroen piccaso xsara, 2006 1.6 diesel. I will google for common faults on my car.
I drove the car today no problems but I know it will happen again when I least want it.
Thanks

Graham, July 2019

Get the codes read for starters
You didn't bother to say the exact make, model and year if your car
We'll need that before anyone can do a G##gle search (which YOU could do anyway) and see if there are common faults with those symptoms and fault codes, for that particular make and model.
With luck you should be able to find an enthusiast forum for your particular car, which may prove more fruitful than here.
Of course, that assumes you are prepared to do the legwork.

Hhfd, July 2019