1988 Pontiac Grand Am - EGR valve test failed. Need advice on as to why.
brand new egr valve holds vacuum and opens properly with engine off but will not when engine is idling this causes egr valve test fail. i would like to know why the diaphram would hold vacuum and open valve with engine off but not with it running
Answer:
Sounds like a possible defective EGR valve vacuum solenoid. We recommend tracing the entire EGR vacuum system. You'll need to inspect the backpressure valve (if equipped) and also the vacuum solenoid for the EGR valve.
posted by SmogTips Support
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