Help with starting/ shutoff issues

[Tinks04]

I tried to post this this morning, but it didn't seem to work. I am sorry if it is a duplicate.
I bought a 2004 Chevy Silverado about a month ago. We had it checked (after a 40 mile drive to the mechanic, nobody really does diesel here locally) pre-purchase and the following codes came up:
U1000,C0306 A&B Motor, CO327, CO 359-4LO Malfunction, CO 379 Front Axle Malfunction, CO 500 CCU Malfunction, BO 790 Case, D 2725 Motor Switch Malfunction, U1301 Class Data Link


The mechanic cleared in and when they didn't show up again, said it was a good buy, so we bought it. Our regular mechanic went over it and changed the leaky water pump and a bad carriage bearing and that was all he could find.
500 miles later it is having issues. It may or may not - start, lope at the idle or stop running entirely. In it's defense, if has never left me on the road. It only stopped running 2x, both times in the driveway at an idle after being difficult to start. First thing in the morning it is fine, the starter turns over 2x and it catches. When it warms up is another story. It may start almost immediately, or it could take it turning 7x, if it starts at all. It doesn’t always lope, and I have not found any rhyme or reason to it, it just seems to come and go. We changed the fuel filter, which was half full of air. This didn't solve the problem so we figured it's a fuel delivery problem. We did the fuel filter housing kit and a couple of hoses that looked dry, had heard this was an issue on this model.


I drove it to work yesterday, about 15 miles. It started fine for me, 2 turns on the starter and on, both at 5 am and at 3pm when I got off work. I let it idle while I yapped with the boys, about 1/2 an hour and it never shut off or loped. I drove it to the dealer- no problem. Drove it all over town, about another 30 miles. I left it with hubby to drive the 6 blocks from where he was to the house and he had to try to start it 4x, (without pumping the primer pump) with the starter turning 10x or more before it finally caught and ran. He and our regular mechanic hooked it up and these codes showed up:
U1255 class 2 communication malfunction, U100 Class 2 Data link malfunction, CO550 ECU Malfunction, BO 790 Transfer Case Neutral Indication Circuit, B 2725 Mode switch Circuit Malfunction.



It is the 2004 LB7 motor, vin code 1, not the 2004 ½. I know these motors had issues with the fuel injectors but they were changed by Chevy in 2005. I can’t really see it being injectors, as they were already replaced and if it were, why is there no smoke, why does it run with all that air in the fuel filter, and why is the problem intermittent?
Does anyone have any idea what the problem might be, what these codes mean or what to do from here? I love my new truck and hubby is ready to pull a shotgun/hammer trick on it.
Thanks for your help.

[rapidoxidationman]

Sounds like an air leak in the fuel line to me, judging by what you've said about the fuel filter being half filled with air... You might consider having your mechanic do a pressure test on the fuel system - seems like I've heard of some guys pressurizing the system through the fuel filler cap then looking for leaks along all the lines. Until the fuel reaches the high pressure fuel pump, the lines are under a vacuum and will suck in air given the chance (unless you have installed a lift pump).

By the way: Have you put the truck in 4wd yet? I wonder if all those codes you erased are related to a transfer case or front end problem.