new to the forum, own multiple diesels, and the 2004 jetta tdi engine code bew is the only one i feel i need a german engineer in the trunk. shuttering started about 2 months ago, no codes until this morning. it has a 2 micron cat filter set up, and the system has been on the car for a year. filters changed every 10,000 miles. the car has 139,000 miles on it. i have a friend that has vag-com and ran the software, found a dtc 18076= pd unit injector intermident fault, along with dtc 16687 = cyl #3 misfire The shuttering only happens in the morning or afternoon, after the car has set for over 7 hours. Air tepm. does not matter. when it happens, you can cut the car off and re-start it, problem goes away most of the time. It feels like a gas engine with a bad ignition miss. If anyone has had this problem or can help, please chime in. multiple shops have looked at, and have not been able to find anything.