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a stuck open egr valve can cause a rough idle,( creates an interenal vacuum leak) but The map sensor will show low vacuum and the vehicle will be running rich. map sensor reading wrong will usually cause hesitation on acceleration or rich running due to low vacuum reading.(both usually set a map code) need a scan tool and read what the sensors are doing, otherwise just wasting money throwing parts at it. do a compression test, see if there is a low cylinder, Positive you don't have a crossed plug wire? bad head gasket?? coolant full??, compression test would show this, how did the spark plugs look? timing set to spec?, bad engine mounts will cause these things to shake / vibrate also. Does it run bad or just shake?

The plugs were fouled pretty bad.I changed them for the first time since I've had the car. It ran fine before this issue.The idle does smooth out a little at higher RPMS.It does not shake,but idles terribly.I've not done any compression tests.