You should do an OBDII meter hook up and look for codes. You'll probably get a 171 or 172 code. Means vacuum leaks at the common chamber. Confirm this by spraying carb cleaner in that vacinity and see if the idle increases. The VX uses a phenolic common camber gasket that's brittle and cracks, Espescially true if torqured to original factory specs of 18lbs. Thirteen lbs. was later found to be sufficient.