CHEVROLET LUMINA EMISSION

Engine Mechanical Problem 1999 Chevy Lumina 6 Cyl Two Wheel Drive Automatic How Do You Check An Egr Valve And Change It If Bad

I Have A 2 Check Engine Codes Egr 0401 And Cylinder 4 Misfire 0304 I Have Replaced The Egr Valve And Spark Plugs And Wire What Else Could Be...

I Have 1998 Chevy Lumina My Check Engine Light Is On It Faluting Every Egr Code There Is Even After I Replaced The Egr Value. The Car...