I do not know much concernin your year and model. But, if you believe you have an Air leak you might want to address that first. Not sure but I believe your Engine has seals on the ends of the Fuel Line connections.

I have also read where members with the newer models had to change O-rings on their Fuel Heaters that were causing Air leaks.

You also might want to check threads with EGR issues for your year and model.

__________________
84 300D, 82 Volvo 244Gl Diesel