I just got my car back aweek ago and had the fuel pulsation damper replaced. When got it back, my idle was messed up. It was around 400-600 rpms.vacuum is now at 14-16 instead of usual 16-18. I had to adjust my idle valve and got my rpms up to 800-900. but vacuum is still at 16. anyways when I first start up car and drive it slow until the temp guage goes up to normal, about 10 min.later , i'll get on it and it will start to stutter from 6,000 until redline, it would hit 13 lbs of boost and hold it,but it feel like i'm loosing power. 3 min later try it again one stutter and hauls ***. Still getting little back fire from time. Is this normal, maybe it needs to warm up longer or is it just cleaning itself out.