When mind failed, it stuck closed - that is, 'off'. It SEEMED like the car was peppy-er. But I dismissed it. I backed away from trying to replace it myself and took it to an MB shop that treats me very well.

Anyway, the guy remarked, "The car's been a bit quicker on the uptake, hasn't it?" I told him I THOUGHT it did, but thought I'd imagined it. He then explained what the valve did and why it was there.

THere is no more power, because, when you get on the accelerator hard, the PTCM closes the valve anyway. But there is a delay before it closes.

THe valve being open allows exhaust into the intake, while this reduces NOx, but it also reduces performance.

Go tear around where you have curves, etc. that mean you are on and then off the pedal a lot.
Disconnect the valve.
Try it again and see what you notice.

I find turning the EGR off has as much effect on response as a throttle reset.


Just try it yourself.