Will a engine out of 2002 Mercury Cougar fit in 99 cougar?

Yes, a 2002 Mercury Cougar engine should fit in a 1999 Mercury Cougar, *provided* they are the same engine type and displacement. Both years used the same basic chassis. However, there might be minor differences in some components that might require some adjustments or parts swaps.

Here's what you need to check:

* Engine Code: The most crucial factor. Find the engine code (often stamped on the engine block itself) for both engines. They need to be identical. Different codes mean different engines with potentially incompatible parts.

* Transmission: The transmission compatibility also plays a crucial role. Make sure the transmissions are compatible (automatic or manual) and the same type (e.g., 4-speed automatic).

If the engine codes and transmissions match, the swap should be relatively straightforward. However, even with identical engine codes, you might encounter minor differences in wiring harnesses or other ancillary components which could necessitate some adaptation work. Consult a repair manual for both years to identify any potential issues beforehand.