Had car problems with Citroen C4, all electrics tested - ok?

Citroen C4 broken down 3 times - anti pollution system light came on warning, had just been serviced. (1st time) Depollution light, car stopped & fan ran on, replaced heat sensor, 2nd time, again the same happened but told running too fast on motorway at 70 as burning too much oil which could cause engine prob and told to drive at 50mph. Did for 5 months, no oil loss. Again tried higher speeds on motorway trip - broke down - AA replaced coil and sparks - test reset but went again with fan overworking - told electrics were faulty - all tested by Raaman - no electrical problems - they think it may be a combustion fault ? please help.