Help 05 trailblazer won't run right after engine swap

[Dbtdesmoinesiowa]

Hey guys we swapped the motor in a 2005 Chevy trailblazer with another 4.2. it will start with foot to floor but must release to stay started runs rough has loud hissing noise passenger side of motor. And spitts sputters. We our stuck we done bunch of stuff any help would be appreciated

 

[mrrsm]

Welcome to GMT Nation...

Please ...Hook Up an OBD2 Scanner and list ALL PXXXX Codes in your Next Post.

 

[Mooseman]

We also need to know what year engine you swapped in.

 

[limequat]

I would guess the internal EGR vacuum line is disconnected. Between runners 3 and 4 on the intake manifold.