Lb7 help

Ok I have an 01 lb7 with a zf6 in it. When I'm pulling a long grade especially with a trailer it will fall on its face when you get around 20 psi of boost, let off the throttle and coast a bit and it will come back and run normal most times but sometimes it's still a dog. My question is could it be the waste gate opening and the springs to weak to close it or could it be something else. The truck has 340,000 miles on it and is starting to show signs that it needs injectors again but it fires right up and runs great just heavy haze when started or sitting at a stop light. I currently do not have a way to check codes or monitor anything but any help is appreciated.

Lots of "could be's" without some diagnostics. I'd start by checking supply fuel lines for signs of collapsing, or a plugged fuel filter. Most big name parts stores will check codes for free, or order one of those OBD2 blue tooth scanners and get the app for your phone. You need to check rail pressure when it's doing it, most of the Bluetooth scanners have some data streaming. Typically when the waste gate sticks it's stuck, very rare for those gates to fail though.

You saying its showing signs of another set of injectors would have me checking the high pressure system.

Is it California emissions?

I would lean towards a fuel pressure issue also.

Thanks for the response guys. I will get some way to read rail pressure as soon as possible. It's not a cali truck and the only sign of injector failure is haze when sitting at a stop light. Is there a pressure relief valve on the lb7 rail like on the new ones that could be weakening?

There is, it's not on the rail. Located on top of the "Y" bridge for the intake. I've only seen a few fail, I highly doubt that's going to be your problem.

Do you have a lift pump?

No I don't. Truck has been bone stock from day one. Is there anyone that is from the Dayton, Ohio area that would be able to check the rail pressure for me I'm currently working in the area.

Look on Amazon, those OBD2 Bluetooth scanners are cheap and the app is free or a few bucks. Super handy to have around. 25-30$ isn't much to have the ability to check codes and see data.

Please note, I don't have one and haven't used one, but friends have and do with good results.

Yea I will have to order one. Thanks for the help