Awful clattering on the highway

[moose-tek]

I was poking along on I-40 yesterday, slowly inching my speed up to 65. Suddenly there was this loud raucous CLAAAAAAAAAAAKK and a huge black cloud pukes out the back.
It happened 2 more times as I fell back to 55, but they were shorter blips. The sound probably compares to what an exhaust brake (jake brake?) would sound like.

Any ideas on what this might be?

[asavage]

You have either a failed injector (nozzle not closing and/or leaking fuel) or if you have a PCV system (OEM or rigged), blowby crankcase oil is being reburned via the intake. More likely an injector. Sorry for the bad news.

[goglio704]

This may not be terminal. When I first had it, my original diesel Maxima did this or something similar. It sounded like an open exhaust or some kind of rev limiter. It went away after a time. I have often wondered if it was a leak at the EGR. Maybe it stuck closed at some point and the noise quit? I don't remember there being black smoke however. I know it used to startle me something awful. It would do it under acceleration. Maybe not the same condition, but I have always wondered what it was. At the time, it discouraged me from sinking much money into the Maxima. I think I gave something like $800 for it. It had substantially less than 100k on it at the time.

[asavage]

On the Maxima/LD28, the EGR system combined with the crankcase vent system, combine to coat the intake ports and intake manifold with thick sooty/oily goo. Under some conditions, some of this goo will come away from its moorings and get ingested. Smoke, surging and startlement. It would happen about once a week on my '82 Wagon until I pulled off the intake manifold and cleaned it, and cleaned and vacuumed out the intake ports.

The old SDs do not have an equivalent problem, until you get into the SD25, and even then I haven't heard anyone mention it.

I'm sticking with a bad injector guess.

[Carimbo]

I was poking along on I-40 yesterday, slowly inching my speed up to 65. Suddenly there was this loud raucous CLAAAAAAAAAAAKK and a huge black cloud pukes out the back.
It happened 2 more times as I fell back to 55, but they were shorter blips. The sound probably compares to what an exhaust brake (jake brake?) would sound like.

Any ideas on what this might be?

Your description is so close to what I've experienced as the engine ingesting a piece of crud from the intake tract. See this post, Intake Grunge.
That Jake's brake sound, combined w/ a momentary loss of power, and a large brown cloud out the tailpipe. Infrequent intervals, maybe 4-5 months apart.

[asavage]

I have to apologize for my faulty advice upthread: I confused moose-tek (LD28) with moose60 (SD22).

Had I realized you had an LD28 (and that we are posting in the LD28 forum), I would have mentioned the intake cleaning first off. Sorry.