TransAm9585

for about the past few months now the shifter moves fine, but and goes into gear, but it doesnt read right. Its only slightly off but it doesnt notifiy PARK. Now i did notice that if i go into geaer and push over on the whole console it reads right. And tonight while driving it now shifts into park just fine read and all, im stumped. I cant trace it back to one thing. But i do have a little thump coming from somehwere up front by i think my drivers feet, it happens when i let tap the gas and let off again right away, its not an engine noise i got that narrowed out, its something hitting i just dont know what. The car drives fine, its killer in speed and shifting its fine, but just these little things annoying me. Iv had it check everything from U joints to brand new shocks and struts, no help. Any information would be apprciated.