I have a 2003 civic 1.7L. The alternator came lose and fell off the car. it broke the tension bolt and was just setting in the area were it sits. Had it tested and it passed so I put it back on. Now when I start the car it idles up and down from 1000 to 500 rpms for about a minute or 2. Then all the gauges die and it idles correctly. But when I put it in gear it hits very hard. I'm out of ideas and hope that someone can help.