tire problems...

i baught a 2000 chevy malibu back in August. 49,000 miles now has about 54,000 the same weeke that i baught the mali - they got bran new tires for it. well about every 4 weeks or so i see that my tire pressure is going down. they said nothing is wrong with the tires. that there just may be a slow leak. i took it to a tire specialist... they informed me that nothing was wrong as well. i dont know if it my tire problems or if it the way that i drive. also when i go over big bumps i hear a big like rough squeek. like my enlignment.. should i take it back to the dealer ship to have them look at it or what?? plus i dont know that much about cars so i dont want to sound that supid about what im talking about... can anyone helppp??? girl in need... !!!!

A 2-3psi loss in tire pressure over a month or so's time is common. I recommend that you get a tire gauge and keep it in the car. Then when you get gas and while its pumping, just check the tires. If they are low, then add a little while your there. This has two major benefits - 1. The gauges on the air machines are often not correct and vary from machine to machine. By checking with the same gauge each and every time, you have an established baseline and aren't thinking your low when its just a different machine, etc. 2. By keeping your tires properly inflated, they wear evenly, last longer and yield optimal fuel efficiency. As for the squeak over large bumps, unless its unusually loud - loud than in the past - its probably normal. If its noticably louder or different than what it has been in the past, it would be worth further investigation.