Tapping noise

Ford Escort, automatic, 154000 1.9 engine. Hi guys, Had the car towed home the other day. The problem is, it will start, to keep it at a idle I have to keep my foot on gas petal. At the same time tapping from valve train. Took valve cover off and with screwdriver to my ear found tapping coming from number two cylinder intake valve. Put a new timing belt on it 10 months ago also checked to see if it jumped, all looked good. I'm thinking broken valve spring. Need some advice. Thanks