|Adventures Under the Hood|
The EGR Valve is just above the exhaust pipe in the middle of the engine. It's purpose is to recirculate a portion of the exhaust gas back into the intake manifold, reburning it and keeping combustion chamber temperatures down, which aids in reducing emissions.
This is an original EGR valve, viewed from above and in front. The pintle is visible where it enters the exhaust manifold.
You can easily check for proper EGR operation by briefly cracking the throttle open so the engine reaches 2,500 rpm or so. You should see the pintle move slightly.
If it doesn't, check for ported vacuum at the EGR. The engine must be warmed up for this test. The EGR should NOT move if the engine is cold. If it does, this could indicate a bad CTO valve.
If there is ported vacuum at the EGR valve but the pintle doesn't move, it is either stuck or the vacuum diaphragm is leaking. If you have the OEM type EGR valve where you can reach in with your fingers and touch the diaphragm, you can do a further test.
The EGR is easy to remove. Check it and the manifold for a buildup of carbon deposits, which you may be able to clean. A new EGR valve costs about $70. Be advised that even a new EGR valve will not hold vacuum, so don't make the mistake of assuming this means that it's defective.