Dr-21: No Fault Code Mechanical Test

At this point in the driveability test procedure, you have determined that all of the engine control systems are operating as they were designed to. Therefore, they are not the cause of the driveability problem.

The following additional items can not be overlooked as possible causes of a driveability problem.

1. ENGINE VACUUM
   
   Must be at least 13 inches in neutral.
2. ENGINE VALVE TIMING
   
   To specifications.
3. ENGINE COMPRESSION
   
   To specifications.
4. ENGINE EXHAUST SYSTEM
   
   Must be free of any restrictions.
5. ENGINE P.C.V. SYSTEM
   
   Must flow freely.
6. ENGINE DRIVE SPROCKETS
   
   Cam and crank shaft.
7. TORQUE CONVERTER STALL SPEED
   
   To specifications.
8. POWER BRAKE BOOSTER
   
   No internal vacuum leaks.
9. FUEL CONTAMINATION
   
   High alcohol or water content.
10. FUEL INJECTORS
    
    Rough idle may be caused by injector control wire not connected to correct injector.
11. TECHNICAL SERVICE BULLETINS
    
    Any that may apply to vehicle.
12. ENGINE SECONDARY IGNITION CHECK
    
    Any abnormal scope pattern.
    NOTE: Any one or more of these items can give a driveability related problem. They can not be overlooked as possible causes.