Bubbles on dipstick...

[PKRWUD]

Dark 5.0
I remember that.

Hozer
What is the vacuum at idle?

There is an easy test you can do to verify if it is an internal vacuum leak from the intake to the lifter valley.

1) Hook up a vacuum gauge to the intake manifold.
2) Fully close the throttle plate by backing out the idle screw all the way.
3) Plug up the PCV valve opening.
4) Disconnect and plug any vacuum hoses attached directly to the intake manifold.
5) Disconnect the wire to the positive side of the coil.
6) Crank the engine and observe the vacuum gauge. From 3" to 7" of vacuum (at a minimum of 250 cranking rpm) is normal. A defective intake manifold gasket will give, in most cases, a zero reading.