Cat C7

[dstock50]

Out bound for propane, up and over the mountain all normal, decreased speed used engine brake and released, lost power 10 mph max, thick black smoke, after a couple city turns, full power, drove more than 10 miles no problems return, Full tank of fuel, start up each month and drive.
2008 Safari Simba < 15K miles, oil change each year.
Question or advise welcome

[Big_Katuna]

The timing of engaging the engine brake and it sticking add up.
Also the low miles; sitting a lot = sticky valve.

[wolfe10]

Any check engine light/codes??

Wonder if the exhaust brake failed to open (mechanically stuck shut, then released). If it happens again, pull over at first safe spot and visually check to see that the exhaust brake butterfly is OPEN.

If this is a PacBrake, here is their lube chart: http://pacbrake.com/supplemental-brakes/prxb-exhaust-brakes/maintenance/