What else than springs can cause rear height drop?

When I bought the car 12 years ago, it was balanced and I think there was about the same amount of clearance in the wheel wells and aero rocker panels were about the same height from the ground both in front and rear.

Some years ago I noticed that car seems back heavy and rear height has dropped. I bought higher tires to rear.

Now, I finally changed rear struts and springs, but it did not fix the situation much, the rear is still lower than front. In front of the aero rocker is about 2cm higher than in rear, and rear wheels are about 1cm higher than front.

So, what else could be wrong?

OE Springs often Won't cause this problem. Aftermarket springs can and often will.
Replacement struts could wrong part even if box/catalog say is right.

Control Arm bushings maybe bad. But that bad to see very easy is likely to cause other suspension problems.
84-87 Cradle and it's bushings could be bad.
These may not cause other problems except under a set of conditions. Example: Turn normal maybe fine and have problems turning hard left, right or both.

Having crap in the cabin or trunk can make car sitting low. Worse for crap in trunk because that weight is Behind the rear axle.

Could be rear isn't low but front is too high. Or rear a bit low and front a bit high. Either is possible when shocks and struts are not same brand and type. Using non-gas units on one axle and gas unit on the other is known to cause problems. Mixing brands/types can to same.

Engine/trans swaps may cause same if either or both are heavier then OE setup.

Check on very flat very level concrete surface w/ good measuring tools to various parts of car's frame.
If front/rear tires are Not = sizes then must shim the tires so axle centers are same distance to "ground."
Shim tires by driving on metal or wood.
You could jack to shim the tires but need to drive off and on to "reset" the suspension before measuring the frame. (Driving just 1 - 2 yards should cancel jack winding up the tires and car.)

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 01-11-2021).]

I did not see mention of the year of your Fiero. But if it is an '88, the redesigned suspension tends to sit that way a bit. That's why I installed a pair of Rodney Dickman's 1" drop lower ball joints on my '88 GT. Leveled the stance right out. Pictures below illustrate this.

With stock lower ball joints:


With Rodney Dickman 1" drop lower ball joints:

This ought to be good.

I had the same problem with my '88 Formula.

I did the red neck thing and installed a set of spring expander units.

The car is perfectly level now, rides and handles just like it did with the saggy ass. Been that way for 5 years now with no detrimental affects.