Cummins N14 twitchy throttle?

This might sound crazy. But it sounds like you could have a broke motor mount.

 

Tps sensor on throttle pedal could have a dead spot. I had one go bad on a 6nz gave same symptoms.

 

I drove a nearly new N14 in the late 90's that had a nasty random glitch that would happen occasionally.

If you eased out the clutch to get rolling the computer would on occasion get confused and start over fuelling which caused the front end of the truck to bounce violently, like a low rider bounces, never did find out what caused it.

Had a few embarrassing moments in that truck, at truck stops and customers I dealt with, can only imagine what they were thinking.

 

What kind of truck? I drove an FLD with the same problem. Throttle position sensor. The leasing company fixed it.

My w9 has a similar problem, but it shows differently. Sometimes when I walk into it, there's nothing there. I back out and do it again, then it works. Whole new throttle assembly waiting for me at KW.

 

Simply put, it sounds like it's the pedal itself. What I mean is when you press the gas pedal it varies the voltage sent to the ecm, and the amount of fuel injected depends on what you demand and the load on the engine.
Ex: ecm send voltage reference (usually 5v) and the return signal to the ecm is 5v, this would tell the computer the gas pedal isn't pressed. 2.5v return would tell the ecm the pedal is pressed half way etc.
This is a very basic explanation of this. These aren't exact specs.
Any good mechanic will always start with the basics before ripping into more complex parts of any system. Hope this helps.

 

You dont need to replace the whole fuel pedal. It has already been said. TPS sensor.