remove the intake hose and the exhaust port screwed into the egr valve, the remove the two retaining bolts from the intake and clean any old gasket material away. if possible run a piece of wire down the hole to make certain the passage is clear of carbon build up
It could be that your EGR valve has failed or has a piece of carbon stuck in it .
heater control valve located on 2001 gmc jimmy 4.3l
Depends on the year. Here is a site that has pictures of an EGR valve for a 1997 - 1999 Suburban: http://www.racepages.com/products/?D=gmc+suburban+egr+valve&Nty=1&Ntx=mode+matchallpartial&Ntk=Main&N=4294950670+4294963366+9926&Dx=mode+matchallpartial&Ntt=gmc+suburban+egr+valve Go to www.racepages.com and search for an EGR valve for your year rig.
behind the throttle body
When my 1997 Jimmy did this , it was a dead alternator. However, The same symptoms in my 1994 came from a clogged EGR valve.
The EGR valve is located in the center of the intake, at the front of the engine, between the alternator and the A/C compressor. I've added a picture of the location to the links on the right. It is titled "Picture of EGR valve location, on 1996 - 2001 4.3L (262c.i.) Vortec V6 engines"
The PCV valve on a 1999 GMC Jimmy is located on top of the engine, on the left side. It connects the valve cover to the intake manifold.
The EGR valve is located on the intake manifold,behind and to the passenger side of the throttle body.
yes they do... Or at least on a duramax
Under your intake manifold. Its a pain to change them, so do them all and clean out thee egr valve too. it is also under there.