[Christ]

Originally Posted by tasdrouille

As Christ pointed out, the MAP sensor will not sense it. I removed this part from my post.

EGR works as long as the pressure in the exhaust manifold is higher than the pressure inside the intake manifold. It is possible to have significant EGR levels at WOT and even at positive intake manifold pressure. In fact, diesel engines always operate EGR with positive intake pressure.

Without sounding pompous about it - doesn't an engine, by design, always have higher pressure in the exhaust than in the intake?

Barring a few very special situations, I can't think of a time that for it to be running properly, it doesn't have more pressure coming out than going in.

I don't fully understand EGR, so that's not a rhetorical question, and I don't mean it to come off that way.