Cascadia driving uphill

I'm driving a Cascadia day cab, probably a '12, with a lawn mower engine atm.
I had my own once, DD15 / 455 it pulled well.
The old saying is " If its not broke, don't fix it." With all the electronic mumbo jumbo on these trucks now, its hard to say where to even start.
Air Filter? Sensor of some sort going bad? Should give you some other symptoms. If the MPG is still good
( 7+), just keep on truckin'. Be thankful its not throwing codes.

 

The one I drive does the same thing. Sometimes it gets better after you shut it off and sometimes it's worse. I'm not sure why I'll need to drop 4 gears with half a load and nobody can tell me what's wrong... if it threw a code they would know what to fix but it doesn't.

"clearing the codes" seems to help for a shot time. Anytime they go in to check it out and clear the codes it runs better. So then they take it for a test drive or put it on a dyno and don't see the problem.

I don't think it's mechanical as it's so random when it happens. When it gets really bad the city horn sounds weak also, sometimes it just warbles like a bird. Try the city horn a few times throughout the day and see how it sounds. Might have the same problem, whatever it is.

 

That's my if it's not broken don't fix it theory. Cause if you get Freightliner fooling around with it, you probably spend several hundred dollars for nothing, and then by them messing with something, now you do get a real $1000 mystery problem.

 

And boy do people hate paying for no problem found work orders. lol

 

I'm no expert but IMO if the city horn sounds weak at the same time the truck isn't pulling good I would guess that the system voltage might be low. Are the headlights dimmer as well?

 

What kind of powertrain do you have in the truck? I drive a 2016 Cascadia Evolution i with the Detroit Integrated Powertrain (DD15 engine/DT12 automatic transmission). Cascadias were built more for economy than speed(mine is slow but on a good day I've been getting 8.6 m.p.g. so far).

 

There have been times they looked a bit dim but not consistently. The voltage display on the dash reads 14.2 every time I check. I'm not sure how it can affect the horn like that and not throw a code somewhere, all the electronics that are in it, you'd think it would detect it somewhere.