repair costs?

You might find the part at a Napa or you might not. This will affect the cost. If it is the valve near the right side next to the firewall? If it is a dealer item alone, it will cost more. This code could be thrown by having vacuum leaks on back side of the motor. Throwing parts at it is no fun either. Just check these few things and report back. I had the same code come up on my DOHC , and it had other problems like a melted vacuum line and a leaky elbow. And hairline cracks on the coil pack which was making it miss, especially when you had the defrost or ac on.