Nissan Repair: infiniti Q45, infiniti q45, pcv system

Question
hi, i'm having some problems with my infiniti... and since there was no infiniti category, i figured i'd come to you.

i have a 1996 infiniti Q45 with 124k miles on it. it got a new engine at around 60k miles.

now my problem is this:

my engine is shuddering, and the RPM's are dropping all the way down to 200-300 or the car is turning off.

also, the exhaust when this happens is smoke: a blue smoke. it does this when in gear... reverse, neutral, and all of the drive gears. it only occurs when i am accelerating from a stop or very slow movement.

do you know what this is?
thanks
sam windler

Answer
Sam,

Blue smoke indicates oil getting past the rings or the PCV system screwing up and sucking oil into the intake.  I would make sure the car is in tune and check the compression of each cylinder to see if there are deep mechanical concerns like blown rings.  On the stumble part I would check for a bak intake hose between the throttle body and air meter.  It is that big black hose that is connected to the engine just past the air filter.