Fox body rear saggs
 

I have a 88 convertible that saggs about 2 inches in the rear , I replaced shocks and springs (brand new) and it still saggs also new upper and lower control arms ,which I didnt grease for a week not knowing , its been a couple months and cant figure it out. Please help

Are the springs to oem spec or are they lowering springs?

The springs I purchased were for a 2003 mustang gt (new) shocks also

That's probably your issue, get suspension parts designed for an 88, not a 2003.

The first set I put in were for a 88 convertible it was sagging the old one were completely shot since the ones for the 88 were still sagging I went with the 03 and it still saggs , was thinking coil ovets for the rear