Hello to all. Car is a '92 300D 2.5 Turbo with 110,000 miles. I decided to have the injectors rebuilt because the engine was running rough. Before removing injectors, the engine was quite. Now after having the injectors rebuilt by a repair shop that specializes in diesels, the engine is nailing at idle but doesn't at higher RPM. I placed new crush washers at the bottom of the nozzles. What can be causing this?

Thanks