P0171 system too lean bank one… probably an air leak after the maf sensor in the trunking somewhere… engines getting unmetered air … the 02 sensors picking up on it and the maf sensor is registering it.
Bank one if I am correct is from the front of vehicle the cylinders on the left .. numbers 1,2,3 with no 1 at the front of engine.

Thanks, I'll check the engine again. I believe the P0171 code was there before I went through a sealed all the Turbo tubing and replaced the intercooler hose on the exit side of the cooler. It only registered the P0101 after this was completed. Your input is appreciated.

OM642 cylinder numbering pattern is:

3 6
2 5
1 4
(Front)

So bank 1 is the right side of the vehicle (passenger side in the US).

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

To all. It took a long time and going to a couple of shops, but, the code problem was finally solved. It turned out the MAF intake "batwing" was not communicating with the ecm correctly and the system had to be recalibrated to clear the codes. I took the car to Power Star Automotive in Greenville, SC. The owner is a former MB master tech and has the factory Star diagnostic system. It took them several tries to get the car to function properly. Thanks to all for the constructive suggestions and input.