Is the 2.2 Ecotec a good engine?
2.2 Ecotec Reliability
Overall, the 2.2 Ecotec is a very reliable engine. 2004 and prior models tend to be less reliable due to the commonality of timing chain failure. 2005 and onwards models don't really have any common problems outside of general maintenance items once the engine reaches high mileage.
Is the 2.2 Ecotec DOHC?
The Ecotec, by comparison, is a DOHC engine with 16 valves (8 intake, 8 exhaust), meaning that it has a camshaft that controls only the intake valves, and a completely different camshaft that controls the exhaust valves. Just like the 2.2, the cams are spun by a chain attached to the crankshaft.