* 2.2L Ecotec I4: This was the most common engine.
* 2.0L Ecotec I4: A less common, slightly smaller engine.
There may have been minor variations within these engine families (e.g., different horsepower ratings depending on trim level), but these were the two basic engine types offered. To know for sure which engine is in a *specific* 2006 Chevy Cobalt, you'd need to check the vehicle's documentation (like the owner's manual or the sticker under the hood).
