Cummins, the continuing saga

Ok, my Cummins was running rough occasionally. I take it to the dealer last week, get a bit of a bs story, a "fuel system" cleaning, and sent on my merry way. Oh, BTW, it's got about 2,800 miles on it,
on '06 3500.
Today, I was sitting in the truck, in park, running the engine at different rpms. Idle seems to be set at about 800 rpms and it will hold that steady. If I push the accelerator pedal to get the rpms to 1,000, the rpms will go from 1,000 to just about 1,100, then back to 1,000. The cycle repeats at about 5 to 7 second intervals. Other than at idle, there doesn't seem to be any rpm I've tried, from 900 to 2,000, that this doesn't happen. It is virtually impossible to hold a steady above idle rpm and the variance is anywhere from 50 to 100 rpms, at 5 to 7 second intervals.
I doubt if this is normal, but if it is, let me know. Otherwise, I'd sure appreciate any opinions on here about what might be happening before I have to go back to the dealer.
Thanks in advance for any opinions.
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sazrac wrote:

Intake grid cycling? Watch the volt meter. When the rpm drops does the voltage drop too? If my heater blower is running on high I can hear the fan speed change when the grid cycles. The headlights even dim a bit when the grid is on.
--
Ken



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Tell me more about that issue. I dont have an idle problem, but on my 2000 I hear a click and the lights in side the truck dim (outside not even on) and another click they brighten. No heater or anything else running.

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GeekBoy wrote:

It's not an issue. It's normal for the diesel engine in the Ram. If you have a diesel engine read this: http://www.dodgeram.org/tech/dsl/FAQ/cold_wx.htm
If yours is a gas engine it's probably the air conditioner compressor cycling. When my heater grid cycles I don't hear a click but when my compressor cycles I do.
--
Ken



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Okay thanks for that info. I got the truck this past April and never noticed it until like a few days ago and its been cold quite often

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