My 1991 200TDI engine functions properly driving around town and never has any issues starting up. As soon as I pass 100 kmH it intermittently sputters and the turbo goes in and out. It has a full tank of gas, all air hoses are connected, and transmission shifts cleanly. I am not a mechanic but am handy. My current search results suggest an air bubble in the fuel system or the fuel pump has gone bad. Has anyone here had a similar issue and/or have any suggestions to repair?