The EGR valve failed. This caused the vehicle to have insufficient propulsion while driving. The dealer has confirmed the EGR valve is the problem. The vehicle is at the dealership. The check engine light came on. The dealer is now stating the replacement EGR valve is a $4000 part because GM stopped making the part when they discontinued the Volt. An EGR valve should cost $250-$400 not $4000. The current trade-in value of my vehicle is only $7000. I cannot get my vehicle fixed due to the cost and the vehicle is too dangerous to drive due to the power loss issues.