The car is exploding on starting and produces a whirring sound. It slowly switches off on idling. Sometimes it switches off on releasing accelerator eg stopping at a robot. The whirring sound eventually dissapears in 10 mins. When in motion it jerks with a clicking sound and revs high. Sometimes it just revs without stepping on accelerator. U sometimes step on the eccelerator and it does nt respond, it may switch off or ma delay esp just after starting. Changed pump, filters, cleaned throttle, changed stepper motor. What cld it be?