The car shakes and the engine revs upon startup.
It is normal for the engine to rev a bit higher than normal when a car first starts up. But, after a few seconds it should come back down to normal. In cold weather, it might stay high for a few minuets. But, if the RPMs are going very high then there is a problem. The idle should go up a few hundred RPMs not a few thousand. A large vacuum leak can cause symptoms similar to what you are describing. A faulty or stick Idle Air Control Valve could also cause this. If you think the RPMs are going up abnormally I would suggest getting a technician to have it inspected for you.
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