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EGR Valve what does it do?

Service engine light has been on. Took it to Autozone to have it scanned. Three different things come up.

  1. EGR
  2. Random miss firing.
  3. Running to lean.

I know the EGR has something to do with the exhaust, but could someone give me better details of its function. Also what will a new one will cost and is it possible to clean the EGR valve?

Could the EGR cause the truck to miss fire or maybe run lean? I have always used mid-grade gas. The truck does have a rough idle and has a mild miss to it. The miss usually comes between 20 and 40 mph. It only misses if you hold the gas petal at a steady speed. Will not miss accelerating or letting off the gas.

I own a 2001 5.3 fullsize 89,500 miles

Reply to
2 Wheels
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The EGR valve introduces oxygen-poor exhaust gasses into the intake mixture to lower combustion temps, thereby lowering NOx emissions. The EGR valve is only supposed to operate at cruising speeds. If the EGR is fubar and opening when it shouldn't (or even stuck open, remaining open all the time) it will cause driveability issues. If the EGR valve is opening too far at cruising speed (like you describe in your post), it will also cause the same problems.

Yes, if the EGR is malfunctioning it can cause misfires and a lean mixture. The O2 sensors detect less oxygen in the exhaust flow, and the PCM eases up on the fuel delivery, resulting in a lean running condition.

You have a linear EGR valve on your truck, which is going to be expensive. You can remove it and check to see if the pintle is stuck open with a chunk of carbon. From the sounds of it, it's opening too far and likely needs to be replaced. If it was stuck open you'd have a really bad idle, stalling, and miss at all speeds.

Doc

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Reply to
"Doc"

Does $119.00 sound about right? havn't had a chance to take it off yet, will have to be a weekend project.

Reply to
2 Wheels

Sounds about right to me.

Doc

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Reply to
"Doc"

Where is the EGR Valve located on my truck?

2001 chevy 5.3 Z71
Reply to
Brian

Is it on the passenger side near the upper front of the motor? Has 2

10mm bolts? 2inch hose?
Reply to
2 Wheels

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