Will a 2002 Chevy Cavalier engine work in 1999 Cavalier?

Generally, yes, a 2002 Chevy Cavalier engine should work in a 1999 Chevy Cavalier, *but* there are important caveats. The compatibility depends heavily on the specific engine code (found on a sticker on the engine block) of both the donor (2002) and recipient (1999) cars.

Factors to consider:

* Engine Code: The engine codes need to be very similar, if not identical. Even minor variations could lead to incompatibility with wiring harnesses, sensors, and mounting points.

* Transmission Compatibility: The transmission from the 2002 Cavalier must be compatible with the engine and the 1999 Cavalier's transmission mounting points. This is a critical aspect often overlooked.

* Wiring Harness and Computer: The engine's wiring harness and computer (ECU) are likely different. You may need to swap the harness and computer from the 2002 car, which can be a complex undertaking. Even then, it might require reprogramming or modifications.

* Sensors and Accessories: Sensors and other accessories (alternator, power steering pump, etc.) need to be compatible.

* Exhaust System: The exhaust system may need modification to fit the new engine.

* Mounts and Brackets: While the engine bay is similar, there's a slight chance of minor differences in mounting points that could require adjustments.

In short: While it's *possible*, it's not a simple bolt-in swap. You'll need mechanical knowledge and experience, and potentially specialized tools. It's best to verify the engine codes and consult repair manuals for both years to confirm compatibility. Mismatched parts can lead to serious problems.

If you're not experienced in engine swaps, it's strongly recommended to seek the help of a qualified mechanic.