Hey guys, I picked up a Rebel T3 in a trade from a guy who said he used it one time and no issues, then most of the pics I take it has some weird pixel line across the middle area but not always. See photo, for example, no settings changed at all between pics. I already cleaned the sensor and factory reset and it's still there. Brand new to photography so don't know much about this stuff, any help is appreciated!
see the line top right
see no line here
You should not have attempted to clean the sensor.
The sensor appears to be defective. That is an older model, one which I think is no longer serviced and supported by Canon USA. There are other outlets that could possibly do the repair, but I fear the actual cost would be more than buying a used camera of the same model.
I suggest that you try a new memory card. Format it in the camera, and hope for the best.
"You should not have attempted to clean the sensor."
2nd this. Also it is not a firmware issue so don't try to reinstall it. If you bought a new SD card, formatted it, reset the camera completely, there is little else you can try.
The good news is, you can easily edit that out in post edit, for now.
If you are using Lightroom it is very quick to remove the defect.
You didn't hurt anything by cleaning the sensor (and they really aren't that difficult to clean without causing damage, it isn't like working with nitroglycerin). But a line that shows up so perfectly and in the same place in a set of photos isn't from sensor dirt, a malfunctioning memory card, or anything in the settings.
There is an intermittent issue with the sensor, A/D converter, buffer, or memory write/control section to cause a line to show up in the same place in multiple images. For a T3, it isn't going to be worth the cost of repair and I suspect Canon would return it as not economically feasible to repair if you sent it in for service.
Hopefully you can unwrap the trade, the problem is likely to grow over time.
"You didn't hurt anything by cleaning the sensor ..."
Poor advice Rodger. You can hurt things inside the mirror box if not done carefully. Perhaps you are correct the OP didn't hurt anything or cause this issue. But the possibility for a new to photography to do damage is there.
Common issue is damage to the foam rubber shock absorber. I know of one individual that used so much alcohol she drenched everything inside.