Finally got my rebuild running nice and now when I try to drive it, barely makes it up a hill..
whats could this be?

Its a S4 TII

 

Is it going into boost?

 

Rebuilds take like i think around 5k or something to break in.. So go easy on it...

They need to building up compression before you will start seeing any power.

 

yes the boost is kicking in but you cant notice it...
but its supposed to be this low on power?

 

test the injectors are working properly, and make sure all fuel lines are correctly fitted

 

If the motor wasn't producing enough compression it wouldn't start. A certain degree of compression is neccasary to even get a motor to run. It takes time for the apex seals to seat (the purpose of a break in) but the lack of power he's describing should in no way be influenced by a break-in period.

btw, you don't need a 5k mile break in, 1500 miles at most.