Cummins fuel problem
 

05 5.9 common rail 6 speed stock no programs just straight pipe. Drives sometimes fine and other times more than half throttle with shut off the engine and sometimes barely easing around shuts off the engine. P0193 high pressure limit too high is code I'm getting only sometimes not continuously on. new fuel filter new fuel pressure sensor and new fuel pressure regulator. Relief valve is working good as did a running test with computer and pressure is tripping at 24000 more or less when engine dies. Any ideas what next to check or anyway I can diagnose the problem. Also the injectors seem to be fine as no misfires or rough idle. 197067 miles