I had a similar rough in gear and smooth in neutral and it was solved with new injectors.

If you plan on keeping the car long term, I would go to auto zoo, and buy a mity vac for $30 or so bucks. You should read a minimum of 13 hg, 15hg being ideal. Make sure everything is off (climate control).

A cheap test to see if your injectors are clogged is to buy a bottle of redline fuel additive. It can be found on amazon. If you notice a significant difference, (positive) then I would do fuel filter, then new injectors. Injectors are pricey....

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Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2