early '99 F250 PSD

Just something that I have noticed before but finally asked about it. When I accelerate hard, the engine revs up fine and runs hard. But when I let off the accelerator and the engine idles down, it sounds like a heavily cammed gasser. Kinda like romp, romp, rrrrrrrr. It's like it is missing on a few cylinders as it is idling down. It quits once it is at idle.

I have no issues with the truck, it runs great actually. Just something I noticed and was wondering if it was normal.

 

Mine does that too. I believe it's normal engine/Torque Converter/tranny interaction. Load/no load...load/ no load back and forth depending on speed
t/c engage/disengage. I might be wrong. Anybody else?
Nut

 

I notice it as well. Maybe it's normal.

 

Mine doesn't do the romp romp unless I am idling in gear around 1200. I think it is because the PCM is having a difficult time adjusting fuel for a rapidly changing load. some injectors are firing, some are not.

BTW 6 speed tranny

 

Well, now I know mine isn't the only one that does it. Thanks for the responses.

 

I call them "luggits".
I just replaced all my injectors and it doesn't do that anymore.
A small price to pay, IMO.

 

mine does it too, I actually kind of like it