RCAV8TOR, I was hoping you would respond. Went back out today for troubleshooting. Replaced the regulator, still same problem. Pulled inlet tube out of injector holder and checked last chance screen. It was ok. Pulled the injector and inspected it. It is not new. The guy that replaced the injector holder probably has the new one, that Im told comes with the injector holder. The injector was clean with only small traces of tar. I put my ear to the injector while it was running and I could hear the injector pulsing. I took the boost injector out and put battery voltage to it, and it works fine. Put everything back together. Went into the on board diagnostic system. Checked to see if the O2 sensor was switching. It was stuck on lean.
Now this is with the pressure sensor hooked up properly. Put it back like I found it with the extra sensor plugged in and hanging from harness. Found with this set up that the O2 sensor was switching normally. Then I checked to see if the injector pulse was swinging. It was indeed swinging but I don't have specs as to what the parameter is suppose to be. I even tried the on board air fuel reset, with no luck. I was about to give up for the day, she was sitting there idling. Sounding like it was running on 2 cylinders and it stalls. I look at the display and find code E-43. From searching this forum I found that Cat has a bulletin out for this issue. Same symptoms. Injector pulse not right, not allowing ecm to switch from closed to open loop. Going to order the main injector tomorrow and see what it does. Let me know your thoughts.