98 Silverado 5.0L K1500 intermittant P0404 code?

Question

Hello all, Twice in the last month the Check Engine light came on for 3 days or so, then went back off. I scanned it and obtained the P0404 (EGR Flow/Performance) OBDII code. This truck uses a linear electric EGR valve instead of the vacuum driven style that I have dealt with in the past (83 Elcamino). I was wondering if anyone had any luck cleaning these and what the odds are that the code may be caused by another problem or sensor out of tolerance. I have yet to experience any stalling or hesitation. The idle is a tad rough at times but I don't hear any miss at the tail pipe. Truck currently has 38,000 miles. Cheapest price for this EGR valve I have found is $100 and I believe GM's was $160.

Any words of wisdom, experience, and opinion welcome. Thanks in advance, Mark

Jeremy Bomkamp · Accepted Answer

I don't think you will fix this problem by replacing EGR..  You may findsomething by removing the egr and cleaning the ports.  I know on thevehicles with the early linear EGR system that the PCM would check EGRperformance while the vehicle was going downhill with no throttle by openingthe egr and expecting the MAP sensor reading to change

Antennaman · Answer

Thanks Jeremy for the response.Now that you mention it, the light did come on the first time after toppinga hill and coasting down the other side.  The second time was coastingtoward a turn off on the highway.  The light has been out for the last threedays now with no troubles.  When I get the chance I think I'll give cleaninga try and give the connectors and wiring another look.  Earning a living asan electronics technician in another field, I've learned the hard way thaterror codes can be both useful and misleading. :)Mark

Marc Porter · Answer

Just clean it with carb cleaner. It worked for me. 98GMC 5.0

98 Silverado 5.0L K1500 intermittant P0404 code?

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