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John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9176
Experience:  A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
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2003 impala: flow..replaced the egr valve.

Resolved Question:

my 2003 impala has code po401 insufficient egr flow. I have replaced the egr valve. What else could be wrong?
Thanks, Ron
Submitted: 7 years ago.
Category: Chevy
Expert:  John replied 7 years ago.



This condition is caused by a restriction of the drilled hole in the upper intake manifold being plugged with carbon.Remove the EGR valve & clean the carbon out with a flexible small brush or similar tool.Residue should come out in the intake .I remove the throttle body to get easy access to the EGR internal port,better cleaning the chunks than running them through the engine.

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