1995 Volvo 850 100k miles....

Yesterday I took the car in and had the radiator and thermostat replaced. Today the car threw a P0402 code and is "surging" a little. I understand the P0402 is related to the EGR. I'm wondering if there is any way they could have broke or disconnected something yesterday during the repair. Just seems really suspicious to me that the car is idling perfect before a repair and immediately after the repair it's acting up.

Really getting sick of taking this car to the shop

 

Either it was just a coincidence, or they accidentally pulled off some vacuum lines (like maybe the ones going to the EGR valve.. or its pressure sensor..?) and either left them un-hooked up, or they reconnected them incorrectly. It's a WAG...

 

I think i'll take it in on Monday and see if they can tell if they missed something.