i am geting ready to turbo my vert.  one problem is that 3000 rpm i start to feel a tap/knock till aroud 4000 rpm.  i can't figure what the problem is.  the car is a 3.1 auto in a 1994 convertible
please help 
thanks
 
if you got a knock at that rpm, whyt would you go boost? are you trying to blow your motor up? unless you had plans eventually on getting a new motor. in my opintion I would just get a new motor then go boost.
**changes are here**
 
 
naw the motor is good it only makes that noise after runnning for a while.  the motor has 40,000 miles(most are highway miles) ( i know they are highway miles cause i drove them).   could it be the transmition or motor or tranmition mounts.   the noise only happens in 1st gear   
please help 
thanks