Unresolved Tilting on x axis - how to fix?

I uploaded a picture of what happens when I try to print something. The first few layers are shifted, but the upper layers are not (only on x axis). The picture shows the same shifting, from printing the same part out with 90 degrees rotation.
I tried using lithium grease but that has not helped. Anyone have this problem and know how to fix it?

 

I had a print that looked just like that today.
I my case it was because I was too slow removing a "booger" off the print while it was printing and the head hit my hand and jogged it. All levels after it hit my hand were off.

Possibly you have an obstructions that got hit too?

 

I checked the head and there were no visible obstructions. I'm thinking it might be due to the x axis moving more easily in one direction, but lubrication did not fix it.

 

I'm 100% sure that it could not be the part, since other parts have similar problems.

 

I've checked and tightened - no differences. The strange thing is that it only tilts for the first 10 or so centimeters, then prints straight.

 

belt tension or the set screw on the pulley.