So my buddy just pulled a blown d16y8 for a new jdm d15b. Everything went smoothly but now the car doesn't idle right and the vacuum reading fluctuates between 13-15 which is pretty low. Check/cleaned the iacv and looked for vac leaks but found nothing. Out of ideas any help is appreciated.

 

Get some carb clean and start spraying around all the vaccum hoses and possible leak spots. The idle will rise when you get it. You should have more vaccum at idle anyway. More like low 20's

 

The IM gasket is new, we'll try the carb cleaner. Yeah the vac readings are low that's why I'm thinking there's something wrong with the motor.

 

my ls is doing this too, only pulling like -15 at idle and it gets annoying but does ilde anywhere from 700-900.

 

that happened to me and mine was the ferrule on the boost gauge not being crushed.

 

i didnt tighten the fittings on the gauge side and on the vac line that i connected it to enough. you got to really crank down on them to crush it. from what i hear, three turns past snug is whats needed for brass pipe fittings

 

check your valves and if its not that could be valve guides, i adjusted mine and now its pulling -20 steady.