Engine control light goes to the Lacetti..please for help

Hello together… I have a big problem and that before Christmas =( Since 1 he week lights up the motor lamp at my Lacetti every now and then I was reading out at Bosch today and they said the misfires are displayed and I can adjust to good 1000 euro! But I didn’t have that much and I depended on the car.. Now a little history: Since I have the car 40.000 tkm now 60,000 tkm it is sometimes happened that he often when he was cold k a gas has assumed as if I was omitting gas.. was there already on the diagnosis device but did not show anything. Now recently a well-known has changed the timing belt (learned car man and learned at Opel). he has now looked again and says that the both noch shaft wheels stand exactly on ot.. I really don’t know what to do now only in the factory city I can’t pay unfortunately…=( That’s why I turn to you evt one knows a solution.. Gruss