I've come to the conclusion that the EGR valve has gone bad....i.e. erratic idle and sputtering when trying to maintain a steady RPM. When I pulled the vacume line off the top, there was no change in this erratic condition. When I put my fingers under the diaphragm I can feel it moving in cunjunction with the rough idle. Is there a way to render this thing static? It looks like a pain in the ass to replace.
Removing the vacuum line will disable it. However, the valve should be closed at idle anyway, so if your sputtering at idle is due to an EGR malfunction (and it certainly could be), it probably means the EGR valve is stuck OPEN...and this probably isn't due to the vacuum. There may be a piece of carbon or flashing stuck in the pintle of the valve, keeping it from closing fully. It does look like a complete pain to remove, but I think that is what will be necessary (for you to clean the junk out of the pintle), provided that your problem is indeed the EGR valve.
To permanently bypass it you will need to fabricate a block off plate out of at leat 1/4 in thick steel.I would just replace it with another functioning EGR Valve or try to clean the one you already have.
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I strongly urge you to diagnose the problem and if it is your EGR valve, replace it with a functioning unit. The EGR does more than re-circulate exhaust gasses for emissions. The gasses also help to lower the combustion chamber temperatures. Lower combustion chamber temperatures help to reduce spark knock and also help to keep your valves cooler so that the valves and their stem seals last longer.
Yeah, and the reduced combustion chamber temps reduce the formation of NOX, which is a pollutant formed when Nitrogen (78% of our atmosphere) is reacted with oxygen (>1700 F). This is not related to Nitrous Oxide that is used to boost power.
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I agree that it should be replaced with a working one. I was just trying to come up with a temporary fix. I'm starting to think that it may not even be the culprit. It does , however run smoother at the constant rpm's. It basically doesn't want to idle, or idles erraticly...
You may want to clean your throttle body. The PCV and EGR valves dump into the throttle body. If the idle air control valve passage is clogged or partially clogged you will have a rough and erratic idle. Be careful what you use to clean the throttle body. Harsh cleaners and stiff bristles or rough scouring pads will remove the coating from the AL. Stick with a soft cloth and some throttle body cleaner or mineral spirits.