EGR question

[notacarlo]

My EGR appears to have charring on the bottom side of the diaphragm. Is this normal on this engine? (97XXX miles)

The car on the highway, at full 15psi feels like it falls flat. It initially accelerates then feels like you back out of it half throttle (boost gauge goes to 15 and does not fluctuate). No codes other than AC command.
No detonation detected while this happens. All other gears feel fine. I know there is a huge load in 5th gear at 55mph when at WOT, so this behavior may me normal.

Thanks,

Dan

[MikeFleming]

EGR has no effect at any positive manifold pressure conditions.

If there's chared marks on the outside of the diaphragm, that sounds like there's a leak in the gasket or tube. Under normal installation, there should not be any exhaust gas near the diaphragm.

[notacarlo]

Then I am replacing it. Just went 150 miles on half a tank averaging 70 mph. Since the egr has a little to do with cruise efficiency I will run a test on the next fill up, new egr and same trip.

Dan