[inafogg]

your discriptions ''heavy in the seat'' &'' I get the feeling that there's something that is "disconnecting" when the suspension travels to its lowest point''.
need a better discription
have you scanned for codes,checked for vacuum leaks?
what made you change fpr a guess,a dtc,or someone said it might be the proplem
take a look at MAP sensor vacuum hose may have a crack i had this before