Dirty Throttle Body

• Stuttering can result from a buildup of dirt and oil in the Trionic-controlled throttle body. The throttle body regulates the blend of fuel and compressed oxygen coming from the turbocharger to a very precise degree. Variations in the mix can cause stalling. Disconnecting the clamps and rubber boot on top of the throttle body and cleaning it with throttle body spray can solve the problem.
  
  

Vacuum Leak

• Stalling can also be caused by vacuum leaks in the 9000's turbocharger system. To cause stalling, a significant leak would have to occur. Check to make sure all of the vacuum hoses and parts are connected to the vacuum system and the connections are tight.
  
  

Dirty Mass Airflow Sensor

• Stalling and stuttering can be caused by the Mass Airflow Sensor or MAF. The MAF measures the air pressure in the vacuum system. Irregular boost pressure from a stuck MAF can cause stalling. Remove the MAF sensor and spray Isopropanol cleaner onto the different elements of the MAF, and allow it to evaporate before re-installing it.