how to sort out my ford galaxy running!!!!!!!!!!!!!!!!?

i had the head gasket replaced on my ford galaxy and ever since it is running really lumpy??????.i suspect that there is an air leak from the intake manifold.as there are two bolts missing from tho manifold.and i believe that the rubber gaskets were not replaced.everything i have read has suggested an air leak from there.....HELP THIS IS DOING MY BRAIN IN.oh by the way it is a 2.0 litre petrol 1998