Stepper Motor Issues on My 3D Printer

Hi everyone,

I'm having some trouble with my 3D printer and I was hoping someone here could help me figure out what's going on.

Recently, my printer (an Ender 3 with a few upgrades) started acting up. During prints, one of the stepper motors—specifically the X-axis motor—starts skipping steps randomly. The result is layer misalignment and completely ruined prints.

Here’s what I’ve tried so far:

Checked the belt tension – Seems fine, not too loose or too tight.
Lubricated the rods and cleaned the axis – No visible debris or obstructions.
Swapped stepper drivers on the mainboard – Problem stays on the X-axis, so I don’t think it's the driver.
Lowered print speed and acceleration – Still seeing the same issue, although maybe a little less frequent.
Motor temperature – Feels warm but not overheating during operation.
I’m starting to think it could be a failing stepper motor or maybe a wiring issue, but I wanted to get the community’s opinion before replacing any parts.

Has anyone else experienced this kind of problem before? Could it be a loose connector or maybe something with the firmware (I’m running Marlin 2.1.2)?

Any help or suggestions would be greatly appreciated!