Transmission

Dodge ram 1500 v6
2001.replaced computer with new
preprogramed one .As soon as I
did light came back on.had it
checked at AutoZone .said it was
gov/pressure switch bad. Alot of
days it starts out in limp mode but
after I get the rpms up it'll finally
go into drive and be alright till I
slow down again . Some days
does fine . Also heater works half
assed and sometimes a/c doesn't
come on until I give it some gas a
few times. Could all this be
caused by some sort of vacumn
leak .or perhaps seeing as how
the transmission trouble started
when I got the new
computer,could that be my
problem