The car is a 97 Z24 Cavaliar with a 2.4 engine. Motor was rebuilt about 2,000 miles ago. The car runs excellent. This is the second time the check engine and ETS light off came on. First time it was taken to a garage and code was pulled. It was assumed it was the gas cap. All was fine for about a month and it is back on with the same code. Any help what to look for? Gas cap?