I've been experiencing a bucking/hesitation off idle and at cruise. To make a long story short, I have the EGR valve capped off right now and that makes the issues go away, so I know I'm going in the right direction.

My question is, why is the EGR getting repeated signals to open to the point of affecting drivability?

 

Vacuum leak?

 

Possibly, but I've replaced every vacuum line I could find. At some point, the EGR was replaced, too.

 

I have to give you points for what may be the first use of "egregious" in this forum!

Bonus points for alliteration, also.

 

Haha, thanks. That's what you get when I'm up late goofing off in the "man cave". I guess what I'm trying to understand is how this unit works. There are definitely some other symptoms that would suggest a vacuum leak. It's running very well, but that doesn't mean something isn't going on. Any tips on how to track them down on an SBO? Any common areas for leaks? Any failure-prone emissions components. Reading the troubleshooting section in the CSM only provided some vague idea that I might have a vacuum leak. Could a failing ported vacuum switch cause leaks? Any ideas would be appreciated. Thanks!

 

There are positive and negative pressure EGR valves. Check to be sure the replacement is the correct one.

 

I'm going to have to look again and take a picture, but I think the replacement valve may be a generic replacement with an OEM# hand-written on it.

The plot thickens...