The shop here in Santa Fe had the car for three days and was unable to find anything that might cause the missing at idle, given that we had already replaced all the filters, o-rings, tensioner shock, s- belt, cleaned egr, new manifold gasket, etc. There are no fuel leaks, fuel is clean and fresh, all systems work, good voltage, no smoking of any kind, fuel mileage and accelleration are normal.

The verdict: software problem in ECM causing shaking during decelleration and at idle.
damage code 54 581 90
remedy according to damage code or diagnosis manual
part # 025 545 55 32 engine control module

The good part is the shop only charged me a nominal diagnosis fee and the ECM is "only" $700 or so.
Has anyone had a new ECM installed for any reason and did it cure the suspected problem, or will this be another part thrown at the car?

Thanks to all who read and reply

Steve

BTW----paid $2.38 for diesel in Albuquerque at 4th st. Phillips 66 yesterday