I need to know the size for the grease fittings on our cars, (specifically a 92 RS) found a few threads but no one knew the exact size. Just knew 1/4 28 was the wrong size

 

grease fittings for what parts? generally the only parts with grease fittings are the front end parts, and those threads can be different depending on what brand parts found themselves ontot he car aver the years.

take one out and match it up at the store?

1/8" npt would be pretty common.