My friend has a Jeep Cherokee (2004) with 110,000km on the clock. It has a problem where the engine management light has now come on, and when using the automatic gearbox, it has become very gutless and lacks power. When the gearbox is changed to manual mode, it performs reasonably. What might be causing this problem? Is this a serious problem. The car-by-car section of this site lacks the information I need.

Thanks in advance

Greg