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!
What does it mean when you snap the throttle and the vacuum gauge goes to the past the 0 mark then vibrates rapidly from +15 to -15 then to 26 and settle back to 21. It should go past 0 then to 26 in a smooth motion, right? 2008 chevy equinox