Entering its second year on the all-new MN-12 chassis, the Cougar did not receive any significant upgrades. In fact, the 1989-90 model years are virtually indistinguishable. Ford began the two-year cycle for the Cougar beginning in 1987, so it made sense that no changes would be made for 1990. The 3.8 V6 continued to be the standard motor in the LS, and the supercharged 3.8 V6 was unchanged for the XR7. On the inside, the Cougar could be optioned with a black interior for the first time in many years. The exterior XR7 monochromatic colors continued to be Black, Bright Red Clearcoat, and Oxford White.

Rumor mills and spy photos showed that Ford indeed was hard at work with fitting the 5.0 V8 motor into the Cougar. And unfortunately it was needed, as the weight for the new cars became apparent in daily driving. The average Cougar was now almost 3700 lbs. and climbing, and every bit of power was needed to propel the cars. Some said that the base 3.8 was not even adequate to get the car going, and that the standard power output should be somewhere in the vicinity of the XR7's motor--roughly 200 horsepower. Ford was aware of the situation from the start, however, and these concerns were fixed for the 1991 model year.