Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I have A 2007 GMC acadia has a DTC p0017 soft code and rattling noise only on cold start for a 2 seconds then itsd gone could it possible the cam phaser