d1mouser, @nurrd , Dana, 2002 Mazda 626 Car shakes when stopped in drive, neutral or park, there could be a few reasons for this problem. There could still be a vacuum leak at a line, intake, base of throttle body, faulty injector, dirty throttle body, IAC sticking/faulty, EGR dirty/faulty,etc.. You should have your vehicle scanned for any stored trouble codes as a first step to help in diagnosing your engines problem. Some of the auto parts suppliers offer free code reading like Pepboys, Nappa, Advanced auto parts,etc and some of the guys are very knowledgeable and may have seen the issue often and put you on the right track. See below some troubleshooting links and fixes for your type of engine problem. Good luck.
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