Q: The steering wheel of my Toyota Etios does not return to center

After I installed new Michelin tires of the same size as the manufacturer specs, a few days later, the steering wheel stopped returning to the center. I got it checked by about five different mechanics, and they checked everything possible they could such as to check the steering wheel rod, suspension, tires, any play or loose connections but nothing has solved the problem. The car has been run very few miles though out of warranty i can't get any help from the manufacturer. After taking a turn the steering wheel returns about 70-80% back but not totally to the center as if something is preventing it from returning. Strangely however though on stationery, the steering wheel shows a return reflex but as soon as car is in motion the steering doesn't want to return. Also, the steering wheel keeps stuck at the same place it was left to, unless maneuvered while driving. I've got all alignment and wheel balancing done 3 times from different places but nothing is helping. TIA!

My car has 37282 miles.
My car has a manual transmission.