1SlowFiveOh:  The 4.0L engines are prone to having timing chain noise. The tensioner fails and allows the chain to slap on the timing cover, often confused with spark knock. It is a costly repair which involves pulling the engine to access the rear timing cover.
2009-05-12 00:05:10

bernie:  If its a constant even ticking only when you accelerate it sounds like a leak in the manifold (where the exhaust pipe joins on).
2009-05-12 01:09:10