my car just started making a poping when i press down on the pedal a little.I thought at first it was my rearend goin out but now im not sure.I can take off easy and get up to about 40 and just press down a little to pick up speed and it will pop then.The only time it does it is after i stop.When i take off it will pop one time and not anymore after that,i have even tried goosin it pretty hard after it poped once and nothing happened.the rearend and ujoints only have about 500 miles on them.what do you guys think?