I'm messing with the EgR on the Volvo.  I hooked the vacuum gage to it.   When I accelerate of cruise , it turns on.  the Vac gage says 6 lbs.  When I floor it.  the vac gage goes to 2-3..  At Idle it turns off.  Seems like 6 lbs is barely opening it.

When I plug  the EGR vac line to a strong vacuum fitting. It opens the egr wide open.  it conks the motor out.

Anybody got any Input?

It also has something called pulsair  that feeds Clean air into the exhaust.  its supposed add O2 to burn off the left over gas.  When I put the vac gage on it opens for like 20 seconds whe the engine starts  then it shuts off and  never came back on.  When I make it stay open,  seems like the engine runs great.  Maybe the O2 sensor thinks it is running lean and injects more gas to the cyl's.