1999 Chevy Lumina egr code 0401

1999 CHEVROLET LUMINA
175,000 MILES • 6 CYL • 4WD • AUTOMATIC
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MBRYANT81
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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. also the engine idles high at random times
Aug 20, 2009 at 12:27 PM
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RASMATAZ
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P0304

Misfiring at no.4 -check the sparkplug, compression and injector for that cylinder.

Engne misfiring can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.
Aug 20, 2009 at 12:49 PM
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