last time one stupid mech misplaced my speed sensor and caused me to see the engine light for over 6months till one day a very good mech helped me checked and fixed it ... becoz the ecu cannot read the moving speed so sometimes it doesnt know how much fuel to inject (sometimes too much, u will hear weird revving, sometimes too less till the engine stalls) ...
if ur speed sensor have problem, its most probably lid up when u speed over 110km/h and doesnt goes off untill u turn the engine off ... another thing to determine is when u r going down a slope, the engine will stall .... lucky car still moving u can kickstart it and maneuver quickly ...