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Message: <blockquote data-quote="shovel" data-source="post: 1588583" data-attributes="member: 29855">The key part of this is that the EGR tube is "upstream" of the EGR valve and the EGR valve is never commanded open while idling, so removing the EGR tube entirely should have no functional effect on idle quality - i.e. no effect on RPM.  That isn't to say leaks shouldn't be fixed, just that a leaky tube or fitting shouldn't affect idle.    If you have substantial amounts of soot in your exhaust it's possible some of that has clogged the orifice in your EGR tube which would give you a DPFE code - the orifice can be cleaned (off-vehicle) with a bath in solvent of your choice.   If the EGR valve itself has been stuck open because of soot then it can also produce that type of code and also affect idle qualty by being stuck open,  plus it's possible to heat damage the diaphragm by constantly allowing exhaust through even at high pressure and volume (stuck open despite being WOT when it would never be commanded open) As a side note, if you do have a lot of soot that's usually going to be because 30 year old valve guide seals are blown out,  they're cheap to replace if you can turn a wrench.   Easiest to do by removing the rockers, filling each cylinder with compressed air to hold the valves up, pull the keepers, pull the springs, swap the seals, reassemble.     Maybe intimidating the first time but it's an afternoon job if you've got the right tools and then you get better mpg, less oil consumption, longer life outta  your cats and oxygen sensors, etc</blockquote>