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Message: <blockquote data-quote="shovel" data-source="post: 1588601" data-attributes="member: 29855">The EGR valve itself is only commanded open under specific conditions,  I don't know the precise digits for a 94 V6 but it's going to be in the neighborhood of this:   operating temp over 160F,  throttle above 15% and below 85%,  engine RPM above 1200 and below 3000, closed loop on.So if the behavior you're seeing is outside of those conditions then it wouldn't even be possible for it to be EGR because it would be closed.Stuff to check - your EGR vacuum solenoid has two ports, the one farther from the electrical connector should go to manifold vacuum.   If you get those backward it will still technically work but it's also possible for manifold vacuum to suck the valve open a little bit and that would open the EGR when it's not being commanded open.Timing - I think your 94 still uses a distributor but I don't know if it uses a SPOUT lockout jumper or if there is another way to lock the timing and check it with a light;  rapid changes in timing from a sloppy worn out chain will cause rpm surges at random times, particular when engine RPM or load is changing.   Wouldn't be a bad idea to verify that timing is consistent.   Look up the spec for your engine, lock out the distributor and it should stay right on that spec not only while idling but also on the way up and down revving the engine.   Usually with a worn chain you'll see it bounce around at idle, lock in when you rev and then bounce when you let off the rev. I have to imagine that the leak you've described is still fairly small like just a "crack" around the flare fitting right?   Even if that amount of air was getting into the engine it wouldn't change AFR enough to do anything especially above idle.</blockquote>