M998 "chugging".....

[Bocephus]

Got the Humvee out last night, its been a while, and once I got to around 50 mph it started "chugging" per say. Almost like the fuel was pulsing or something to that nature. Below 50, and at a idle, it runs perfect just like it always has. I drove it around quite a bit last night just to run it and it did fine in town, but as soon as I would get to 50 mph on the HWY, it would start doing that again.

Any thoughts on where to look first?

Thanks.

 

[simp5782]

It is called a surge when the fuel acts like its cutting in and out. Check fuel pressure from the main mechanical pump to the injection pump. Also check fuel quality. If your pressure is low, the replace the fuel filter and recheck pressure.

https://www.youtube.com/watch?v=hBA0QRg0a8g

 

[Bocephus]

Thank you. That helps. I will start there.