I have a 2014 Volt with 61,000 miles. All of a sudden it seems to be hitting bumps hard. Is this a sign of worn suspension? I also noticed that my new Michelin Energy Savers were reading 44PSI instesd of the normal 38. The tires were actually 44 for the front and 42 in the rear. Could the high inflation make the ride harsh? Any thoughts would be appreciated. The car always used to ride so smooth.