E.G.R. Tips E.G.R. Tips (Exhaust Gas Recirculation) 1. E.G.R. lowers combustion temperature which lowers oxides of nitrogen pollution. 2. E.G.R. is not used at idle. (Would cause very rough or no idle at all.) 3. E.G.R. is not used on cold engines in most cars. (Would cause poor, cold drivability.) 4. E.G.R. is not used at wide open throttle. (Would cause loss of power.) 1. We will assume the fuel and ignition systems are working to specs. 2. If car hesitates on light acceleration, has a tip-in sag, or a flat spot when transmission shifts from first to second gear. Most probable cause is too much E.G.R. flow. 3. If car pings at cruise or light throttle acceleration, and has no pinging under heavy acceleration, the most probable cause is little or no E.G.R. flow. Possible Causes of Too Much E.G.R. Flow 1. Weak calibration spring in E.G.R. valve. Repair: Replace valve. 2. Restricted catalytic converter or exhaust. Repair: Check for exhaust restriction and repair as needed. 3. Idle speed too high. Repair: Adjust idle to factory specs. 4. Wrong E.G.R. valve. Repair: Replace with correct valve. Possible Causes of Too Little E.G.R. Flow 1. Defective E.G.R. valve. Repair: Replace valve. 2. Exhaust back pressure too low. Repair: Check for missing catalytic converter. 3. Plugged E.G.R. passage. Repair: Clean passage. 4. Idle speed too low. Repair: Adjust idle to specs. Visit our Resource Library for available downloads