I have a 2006 ram 2500 5.9 cummins. Engine ran perfect until I had starter and batteries replaced. After that I was getting a code on banks 6 gun tuner saying fuel rail pressure sensor voltage out of range. Then it started surging from 1k to 3.5k and nearly caused me to wreck. Snap on diagnostic showed 1 injector was weak so I bought that and it cured the surge. The mechanic recommended I have the ecm flashed so I took it directly to the dealer and they flashed it. After leaving the dealership when you hit the go pedal hard I had spark knock and it was smoking bad. Had the mechanic ride with the diagnostic equipment and acceleration I'm showing negative 7 degrees timing. Since then I've replaced the cam position sensor, fuel control actuator, map sensor, full set of injectors, high pressure pump, remanufactured ecm and another set of injectors. I have 13k in repairs and still have the problem. Now another mechanic says it sounds like a bad ground. I know this is long, but I just wanna get it fixed. Currently it runs good warm but fuel economy is down from 19 to 14.2. It's got 168k miles. Any ideas would be great