If no difference with golf tee, that eliminates egr as suspect for that particular problem.
I only mentioned that cuz you had the egr code and assumed they were at the same time..[egr is likely plugged tube at intake/head side ] but that would not point to your problem.
As money is always an issue with diagnosis, I recommend trying the low $$/ easy test possibles first..
.. next on the list would be to change the resistor boot plug connectors under each coil .
Common ignition fault and good insurance $$$ spent at the same time.
You may also want to archieves a led/sw tool that will let you get to the ignition pin # 8 for more specific codes... that will give you some direction on both fuel and ignition management faullts..
You may also want to golf tee the purge valve line to the intake , as this is a no $$$ test and will verify that the valve is not sticking open and causing an internal vac leak...again, tee it and try the test run...