Results of Incorrect EGR Operation

Too much EGR flow at idle, cruise, or cold operation may cause any of the following conditions to occur:

^ Engine stalls after cold start.
^ Engine stalls at idle after deceleration.
^ Vehicle surges during cruise.
^ Rough idle.

Too little or no EGR flow may allow combustion temperatures to get too high. This could cause:

^ Spark knock (detonation).
^ Engine overheating.
^ Emission test failure.