The lock I have on my passenger door really struggles.
I really have to force it, takes me like a minute of effort and finally it slides to locked position.

If I use the key from outside, it wont even lock because the key wont turn to the right (struggles).

Is it simply lubing up?

 

try wd40

 

Yeah, you have to pull the door panel if you want to really cure it. Thats the only way to get at all the moving bits.

Don't bother with wd40 though, it doesn't stick around. You need something that wont run off that easy. I usually use some rust check crap from crappy tire and hose the whole thing.

 

I had a similar issue where i couldn't turn the key from the outside. WD40 wears off easily, and from my experience it is a lubing issue...

When i got my car rustproofed, i just told them to spray some of that oil inside the keyhole..worked like a charm...