2006 Low rpm motor shake

[NGuzik]

After a few months of trying different things and thinking about it, I've come to the conclusion I have no idea. What I do know.
-Below 1000 rpm I have a pretty noticeable shake.
-I got the truck with a Aem air intake what was kinda dirty.
-Replaced fuel filter
-oil level was normal
-Truck has 120,000 miles, runs great no power loss
First thing I did was put an oem air box back on it with the thinker 4'' fleet fleetguard filter. The same day I did this it started to drip from the crank case vent tube. It doesnt poor out the drain, nor does it blow the oil cap off with fog. Just a drip a day. So I put the Aem intake back on but cleaned, and it stopped the drip altogether. It seems to me that the thicker air filter made more negative pressure? At no point did the oil level become over full or need to be added to. At this point i'm getting worried about a falling injector or dusted rings. Is it worth replacing the fuel filter and filling it with injector cleaner hoping its a bit of carbon on the tip of an injector? Any ideas? I hate not knowing but I'm pretty much out of ideas...

 

[JR]

Is it an oiled element? Either way, its difficult to find a better system than OEM. K&N's oiled elements for our trucks claim something like 99.5% efficency compared to Fleetgaurd 99.9%. It doesn't sound like much difference but per Fleetgaurd, a filter that is 99.0% efficient passes 10 times more dirt than a filter that is 99.9% efficient.

When I first started reading your post a bad harmonic damper came to mind (noticeable shake). But it sounds like you are describing a miss.

 

[NGuzik]

No it's dry. I wouldn't have bought the truck if it was oiled. I guess i've pretty much talked myself into running a filter full of injector cleaner. Any brands of cleaner better than others?
Diesel 911 > Mopar?