Engine is chugging when taking off but runs good down the highway

What kind of engine?

 

If you have a Cummins ISX we have seen improperly or leaking fuel filters do that. They are actually sucking a bit of air at low rpm, but will run fine at higher rpm. Usually the big seal between the fuel filter itself buckles or splits.

 

Still could be air getting in at low engine speeds, not at higher speeds. I have actually seen fuel pressure on a Detroit too high at idle and the engine will run poorly, but run great on the highway. The first thing to replace is the fuel filters. I would say the injector harness is fine, a problem in the wiring will cause issues at any speed. Is the problem still there?

 

run any fuel treatments in your fuel?

 

Year? 12.7 or 14.0? HP? How many miles on it? When was it last serviced?

Air getting in the fuel lines will do this, usually at the fuel filter. Look for bubbles getting into the fuel filter reservoir when it's running, if you have the typical fuel filter they put on the Detroits, Definetly check the air and fuel filter first, I would change the Fuel filter, you might just get lucky. Low fuel in the filter reservoir can be an indication of a clogged filter. If your unlucky, you could be looking at a fuel pump issue.

Edit:I just realized I pretty much said what Heavy D just said.

 

Better change your tune then!

Can't be gettin caught agreeing with another trucker!

 

Spam alert!!!

 

I only own mechanical injection enginse. Allis, Perkins, Cummins, Detroit. So I'm not sure this would work on todays modern engines.

I use a cutout piece of inner tube with the valve stem still attached, and have a helper put air to the fuel tank to pressure it up a bit (not 90psi), simply hold the rubber over the fuel filler neck while applying air, then look for leaks at all joints in the lines, filters, etc.

Been my experience that plugged filters will only run at idle. When it comes time to put some power to it, the engine falls on its face.

If the idle speed is dropping while backing, or taking off, I'd look to that issue. Governor etc.