Hello all in my 95 5.9 4x4 I got a code for failed egr.What could cause this&how can I trouble shoot this&fix if needed?

 

Means your EGR valve on the intake manifold is shot.
Replace it OR, block it off.

 

How do I block it off&do I need it?

 

Just go spend the $30 at the auto parts store and replace it...

 

Unless it's stuck open (which is unlikely), it's not really hurting anything. Removing it and blocking it off is effectively the same thing as it being there not working, so why go through the extra effort? FWIW I had an EGR code and the valve still worked fine, it was probably the controller thing that failed. You can verify if the vavle is working by taking a vacuum hose directly from the manifold and putting it on the valve, at idle it should run rough if the valve opens.

 

Listen, you block that thing off or don't replace it and you are in an inspection state, it's a FAIL.
If you're not in an inspection state, then some tree-huggin', air pollution hatin', greenpeacer is gonna come from behind and shoot you in the head!!! LOL...

 

Thanks guys&no emmisions here.

 

It varies greatly by state. No visual inspection here, my EGR is gone, truck passes emissions just fine. My emissions were actually better now with the turbo, 42lb injectors, no EGR and Megasquirt controlling fuel than it was stock.

 

+1......... Replace it. Unless you like looking at a CEL all the time.

 

If it was 30 I would its over 100 here.