2.5tdi Developed a severe misfire and almost complete power loss. Cruising along 70mph on motorway after 100 mile round trip and misfire began without warning. Limped home and found 2 fault codes; 01268 Quantity Adjuster (N146) Defect Intermittent 17583 Pre injection turned off P1175 No water in fuel or anything obvious. Think maybe injection pump may be on the way out. Any thoughts on any other checks I could do would be appreciated before I take the pump off and send away for testing.