What usually causes a rough idle on a 2012 Mustang GT?
Documented on the 2012 Ford Mustang GT build
Published April 27, 2026
Common causes include vacuum leaks (cracked hoses, failing PCV grommet), dirty throttle body/electronic throttle plate buildup, or faulty PCV components that let unmetered air into the intake.
Documented In This Build
Related Knowledge
How do I know if the PCV grommet is bad?Can I just clean the throttle body to fix the idle?What torque should I use for the coil mounting bolt?What causes oil to fill the spark plug wells?Can I drive the car if the plugs are covered in oil?How often should I clean the fuel injectors?Can I use a pour-in fuel additive instead of an inline cleaning kit?Can I reuse the old springs with new strut cartridges?
Related Parts
Throttle body gasket / O-ring
Motorcraft / aftermarket$12
PCV valve / valve cover grommet
Motorcraft / aftermarket$25
Vacuum hose (assorted)
generic$10
Brake cleaner / contact cleaner (for quick spray checks)
generic$5
Throttle body cleaner
CRC (typical)$8
Related Tools
Ratchet and metric socket setGeneric
Screwdrivers (flat & Phillips)Generic
Hand vacuum pump / smoke machine (optional)Generic
Shop rags and gloves
Torque wrenchGeneric
OBD-II scanner / code readerGeneric / Bluetooth adapters commonly used
