Dr-22: No-Fault Code Mechanical Test

At this point in the driveability test procedure you have determined that all of the engine controls systems are operating as they were designed to. Therefore, they are not the cause of the driveability problem. The following additional items should be checked as possible causes:

1. ENGINE VACUUM - Must be at least 13 inches in neutral.
2. ENGINE VALVE TIMING - Set to specifications.
3. ENGINE COMPRESSION - To specifications.
4. EXHAUST SYSTEM - Free from any restrictions.
5. PCV SYSTEM - Must flow freely.
6. DRIVE SPROCKETS - Camshaft and crank shaft.
7. TORQUE CONVERTER STALL SPEED - To specifications.
8. POWER BRAKE BOOSTER - No internal vacuum leak.
9. FUEL CONTAMINATION - High alcohol and 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.

Any one or more of these items can give a driveability related problem. They cannot be overlooked as possible causes.