I have no idea?

Could be a clogged air filter, or a clogged dpf not allowing the turbo to build boost. Does it regen at all? If you have a manual regen button you can give that a try. (Note my certs are for light duty diesle trucks and my experiance is 99% Ford related)

 

Not to sound dumb but is it lng not diesel? We had a few freightliners back when I worked at sysco that ran on lng and they had zero torque and ran like how you describe

 

change out the fuel filters and check the air cleaner, a lot of times the fuel filters will get gummed up, especially if your companies shop is way behind. just make sure it's full of fuel when you put it back on.... double check your instruments, there may be a clue if it's running hotter than it should be, any weird smells can always be a clue as well. your mechanic and your dispatcher should always be your best friend LOL best of luck

 

Ask the shop if they can plug it in and force a regen. Might help might just waste 20 min

 

Maybe the engine didn't come with power. as in a smaller engine.

You didn't say what the engine is other then powered by mercedes. Have you looked for a label that might say what the horsepower rating is? Or looked for some type of number to do a Google search.

 

Its old. I have a daycab with 530k on the od. She can run when empty, but put 35k on the deck and im a crawling up to speed. Just old. My truck gets pm'ed regularly, and company has any issues delt with immediately..... just old. But im paid by the hour. So.... i dont rightfully care about speed...

 

And you haven't started to look around for a new Gig???? Are you going to wait until you stuff is out on the curb before looking elsewhere? You should have called into the office while you were waiting at your first pickup, if it ran that bad empty.