An easy way to tell is the front bumper, on the 90-91 the center is like the car is frowning and the 91-92 looks like the car is smiling. And look at the ehxaust manifold, if there is an oxygen sensor on the front of it under the hood then its 90-91 as the 92-93 only have one oxygen sensor near the cat. I have both years in my collection and I checked them out side by side.