Engine options in the XE are: 2.0, 4 cylinder Ingenium diesel (in various power outputs) 2.0, 4 cylinder petrol (early cars used a Ford engine, then a 2.0 Ingenium was used), again in a variety of power outputs. 3.0 V6 Supercharged petrol engine on the 'S' models, 340ps initially, then uprated to 380ps. There isn't a 2.2 engine available in the XE.   Personally, petrol all day long for low mileage use.  

Petrol - it warms up quicker and won't cause you DPF or similar expensive problems. Also the larger the engine in a car that size, the less it has to work hard so better fuel economy as a general rule od thumb. Obviously if you go for a 5.0V8 supercharged then economy won't be as good. Whatever you go for, make sure to give it one long high speed (motorway) run every so often to help keep things cleared out.

Which is best engine on an xe for occasional low milage use a 2litre or 2.2litre. I am looking to buy a 2016ish model.

Welcome aboard! Try the CKP - Crank Position Sensor - these won't give a fault code but will cause a non-start. They also usually fail suddenly. Had that happen on my S Type a couple of years back, fitted a new one on a hunch and fired up immediately. Not sure where in the world you are but give Rock Auto a try in the USA, it's a fiddly job but doesn't take too long.

Hi, New member here!  My 2002 x-type 2.5 petrol, purchased new and with only 80k mi, is not starting.  The car was in storage on a battery tender for the past month.  Initially after taking it out of storage the car started and ran for ~30mins but after shutting it off, it would not restart. - Battery, alternator, & starter are all good (confirmed with local shop) - No error codes It feels like an ECM issue, any suggestions? Best, Sean