Common places for vaccum leaks on 3400

[19Cutlass94]

whats the most common places for vaccum leaks on these motors? Im pretty sure Ive got a leak somewhere, but not sure where. I can hear it when I step into it going down the road, and the idle isnt steady. Any helps is great. thanks.

[BXX]

PCV Vacuum hose assembly is the most common.. Any parts department guy at the dealer will typically say when you call for one "oh, you need one of those peices of crap"

 

 

[rockfangd]

x2 pcv is definately most common, mine pops off once in awhile and i know it when i hear the noise and the idle sits a little higher

[19Cutlass94]

well along with this vaccum leak, i also have a HORRIBLE top en tick that doesnt go away at all. Im thinking either a collaposed lifter or loose rocker arm. but what else could it be?

 

[Addicted To Boost]

Probably a collapsed or sticking lifter. I replaced all the lifters in my GP and its very quiet now

[Brian P]

x2 on that vacuum hose that sits on top of the plenum.... sometimes where it connects to the EVAP purge solenoid it splits or loosens. Sometimes that rubber grommet around that line at the plenum falls off and will cause a leak.

 

Other than that? Throttle body gasket being misaligned or torn.... same with the upper intake gaskets. There really isn't much else. Luckily these engines are much easier at checking vacuum lines than the old 3.1 MPFI's.