loping engin

You can easily remove the EGR valve to inspect it and see if the pintle is being held open by a chunk of carbon or not. I would also check it carefully for any vacuum leaks.

thank u for the advice i went a head and bought a new one since the tahoe has 116000 miles and i bought it used and it probaly has not ever been checked or cleaned had it in to burt chevy in littleton co when i first bought it and they did the intake manafold gasket and injectors and some other warrenty work thanks again, cmfb

That's fine but it would have been nice to know if the old one was closing all the way to confirm that you found the problem. If you haven't changed it yet, look at the old one when you remove it and see if the pintle is seated all the way.