Addy

Hi guys I have owned my 64 plate chrystler ypisilion for the last 4 years. It has never given me any issues, last week I took my car in for a service the mechanic advised it has reached 80,000 would be good to replace the timing belt. Its been changed drives fine but later engine management light will come on reading faults of a misfire cylinder 1 and 4. The mechanic has checked the timing everything is fine. When the engine management light comes on there is no power. Can someone help please