barstard!
[mrow][mcol]Stevie's Tyres @ 4pm[mcol]Passenger[mcol]Driver
[row][mcol]Front[col]35[col]35
[row][mcol]Back[col]34[col]35
Looks as if you've got a slow punture bud. Try the valve test that Gixxer suggested and failing that you will need to examine the tread for nails, screws, etc.