For 1990-2009 cars

#### Special Tools

J 23951 Valve Manometer

1. Verify the air cleaner is not plugged.
2. Remove the oil level indicator. Install a J 23951 or equivalent.
3. Start the engine.
4. Check for a slight vacuum at idle. The vacuum level should be less than 5 inches.
5. If vacuum is equal to or higher than 5 inches, inspect and verify the clean air hose from cam cover to air intake is not blocked or kinked.
6. If vacuum is in the normal range, block or pinch off the clean air hose. The clean air hose is the hose between the cam cover and air intake system. Vacuum should increase on the manometer. If held too long, vacuum will be drawn through the crankshaft seals creating a sucking sound.
7. If vacuum does not increase, the orifice in the intake manifold could be plugged.
8. If there is zero vacuum or pressure, verify compression of the engine.
9. If compression is normal, check for a blocked orifice at the intake manifold. Clean the orifice.

Concern | Action
--- | ---
External Oil Leak | Inspect for the following conditions:

• | Plugged positive crankcase ventilation (PCV) orifice in the intake manifold

• | Plugged or kinked PCV hose

• | Damaged or incorrectly installed PCV hose

• | Excessive crankcase pressure

External Oil Leak | Inspect for the following conditions:

• | Plugged positive crankcase ventilation (PCV) orifice in the intake manifold

• | Plugged or kinked PCV hose

• | Damaged or incorrectly installed PCV hose

• | Excessive crankcase pressure

Rough Idle | Inspect for the following conditions:

• | Plugged PCV orifice in the intake manifold

• | Plugged or kinked PCV hose

• | Leaking or damaged PCV hose

Stalling or Slow Idle Speed | Inspect for the following conditions:

• | Plugged PCV orifice in the intake manifold

• | Plugged or kinked PCV hose

• | Leaking or damaged PCV hose

High Idle Speed | Inspect for a leaking or damaged PCV hose.
Sludge in the Engine | Inspect for the following conditions:

• | Plugged PCV orifice in the intake manifold

• | Plugged or kinked PCV hose