I have 115,000 miles on my CRD. I replaced the timing belt at 100k. I noticed while cruising along at 70 mph a slight loping just at 2000 rpm with very light accelerator applied. No loss of power just that darn loping noise like a detroit diesel 6v72 with ddec II injection system does at idle or light load when the injecters are slightly worn. Problem is it does not happen at idle, just 2000 rpm with light load. I checked for codes and got the 0069 for the boost sensor. Cleaned the sensor and ordered a new one. Changed the air filter and fuel filters, checked the fuel lines and air intake system. Even put diesel kleen in a fresh tank of fuel. Still got that darn roll at 2000 rpm. I don't remember on this crd when the turbo boost is needed. I'm thinking below 1500 rpm and above 2000 rpm with light load. If the new boost sensor does not correct my issue I will check and clean the EGR value to make sure it is seating shut properly. My thinking is that I my be losing boost due to the EGR value being slightly open and when the boost increases enough that it forces the EGR valve completely shut. This may be causing the ECM to compensate the fuel injection to due to a pulsing or erradic boost pressure signal. Next I will remove the turbo and rebuild it. The vanes may be sticking. The kit to rebuild it only runs about $150.00. I don't think it is the fuel pressure regulator or the fuel pressure sensor. It has no knock and runs great, no surging until 2000 rpm under light load. I have been told I can be a little OCD with my toys. Also my CRD has no Mods! I keep my air filter clean and run rottela 5-40 so I don't get hardly any oil in my turbo hoses. If you let the air filter clog up the turbo WILL suck oil out the CCV system and coat your hoses with lots of oil.

Any advise on my issue would be welcome.

I'm NOT a mechanic or expert, but have you checked or recently done any work to your fuel system, replaced filter etc.?

Additional information. It does it while in park and neutral at 2000 rpm. It is acting like when the rpm limiter cuts back the fuel when trying to over rev an engine. It is definitly in the fuel management system. I have a direction to look. But it does this only at 2000 rpm! Not above or below!

Just removed and cleaned my turbo vanes today. I rebuilt my turbo as well, all though the new and the old parts measured the same with calipers. I do not think it needed rebuilding but the vanes sure needed cleaning for more freedom of movement. My turbo had 85K on it. Have a bunch of pics if you have any questions.

I have noticed my motor loping as well. It does it at 1250RPM. It seemed to do it at 900RPM for a little while as well....

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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.

The loping is gone. Received the new MAP sensor Friday and installed it on Saturday. Runs much better and no loping

New project is to overhaul my 1998 dodge ram with a cummins engine. It is all original with 334K. The trans is making a noise when I push the clutch in. The 4 wheel drive on this beast has never let me down.