What you have is called the CIS (continuous injection system) This system meters the air directly by way of an air plate, as this moves in and out in response to more or less air flowing it allows the injectors to spray more or less fuel. So the whole system relies on engine vacume so between the air plate and the motor must not have any leaks.
My first sujestion would be to clean the air plate and run some carb cleaner through the CIS by filling the fuel line with carb cleaner hooking it back up and have someone crank it while you push the air plate in by hand.
Dude, keep in mind that reguardless if they sat for 4 years or not, they are at least 24 years old with who knows how many miles. It wouldn't be a bad idea to change them out.