I have a 2005 Chevy Aveo - It makes a creaking sound when I accelerate or decelerate. It seems to be coming from the passenger side of the car - What might be causing the sound?
Sounds like a motor mount.
One of many possibilities.
IMHO creaking sounds during any change in a car’s inertial condition (accelerating, decelerating, turning, going over bumps, whatever) generally comes from either a chassis busing or engine attachment (like the motor mount suggested by 2-cents).
Other common rubbery bits that get old and creak over time include antisway bar bushings, strut mounts, and sway bar link bushings.
For your reference I’ve attached drawings of the front suspension configuration of a Chevy Aveo. The bar that goes across is the antisway bar, generally just called the “sway bar”. It rotates within the hole in its bushing (item 2 of CNO4230) every time the front goes up and down… which is constantly during driving, especially when accelerating or decelerating. It’s a metal rod constantly rotating one way than the other in a rubber hole. Its hole wears bigger, and its rubber dries up and hardens. I’ve even seen where the bushing has worn a groove in the metal.
Try driving the car safely up onto some good ramps (tires properly centered on the ramps, engine off, tranny in P and paring brakes ON). Slide underneath and spray silicone spray liberally on the bushings. If that affects the noise, you’ll know what to do. The good news is that bushings, sway bar links, and stuff like that are dirt cheap. The bad news is that on some cars changing them is a PITA due to poor access. You can try the spray on other bushing too, and even engine mounts, but do NOT get it on the serpentine belt(s).
Let us know how you make out.