Engine Running

Start the engine and, while idling, check the following:
- Check for plugged oil in the rocker arms or push rods (4.0L pushrod, 5.0L).
- Check for plugged oil feed in the camshaft roller followers, hydraulic lash adjusters or cylinder heads (4.0L SOHC).
- Check for proper overhead valve train lubrication.

If insufficient oiling is suspected, accelerate the engine to 1200 rpm ± 100 rpm with the transmission in NEUTRAL and the engine at normal operating temperature. Oil should spurt from the rocker arm oil holes such that valve tips and rocker arms or camshaft roller followers are well oiled. If oiling is insufficient, check the oil passages for blockage.