HI, I have a 2006 Limited with the 2.8 crd, recently it has developed a very rough idle,
But other wise it runs well and the fuel consumption is fairly normal.
I have cleaned the maf and the map sensors but that made no difference,
any one have any ideas?

Initial thoughts check air filter and bleed fuel filter head, maybe change fuel filter if it's been a long time, and maybe try some diesel fuel/injector treatment.

_________________
Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

See if there is bubbling around injectors from leaky copper washers. If it smooths out around 1500 RPM it may very well be injector washers. Number four injector seems to be a popular one to leak....

_________________
2006 Liberty CRD 275K, JBA 2.5 with Fox Shocks, GDE Turbo Kit, GDE TCM Tune, Suncoast TC, OEM fuel filter housing converted to fit Caterpillar Fuel Filter 1R-0749, OEM themostat housing modified to accept Hemi 203 F thermostat.

Start it up and toss a cup of water on top of the injectors, if you get any spray you have a blow-by injector leak.

After that, I would say change the fuel filter. Start with the cheap stuff first.

_________________
Silver 2006 KJ 2.8L CRD Limited:
GDE ECO Tune / Fumoto Valve / E-Tecno GX3123 7v Glow Plugs / 2nd Gen Fuel Head / Mishimoto RED Hoses / Rockers/Lifters @ 114k / Hayden FC + 11 Blade Nylon / Sears P1 Battery / Transgo 45RFE-HD2 Reprogramming Kit / Timken Front Bearings

Thanks guys I will check those things out.

A failed alternator decoupler pulley will cause this too, especially if it idles rough in drive, and less so in neutral. Check for signs of red rust under the cap on the alternator pulley. Red rust usually means the pulley has failed. See my other post on an upgraded unit from Litens if you have this problem.