Driving around town, driving steadily at 70-80 mph - no misfiring. When going up a hill or entering motorway as i press accelerator harder, engine stutters and engine light comes on. As soon as i take the foot off the pedal, engine stutter and engine light go away. Code for engine light says cylinder 1 misfire.

 

Sorry forgot to ask. I need help in identifying what the causes and how to go about fixing. Thanks.

 

Refer to the attached file showing the cylinder numbering layout of the AJ-V6. Note cylinder one is on the RH bank beneath the inlet manifold.

The coil unit may be shorted due to engine oil finding its way into the spark plug well. The upper inlet manifold must be removed to inspect the three coil units for oil fouling. If oil is present, the cam cover and spark plug boss seals must be replaced. The spark plugs should probably be changed as well given the age of the vehicle.

While the upper inlet manifold is removed, inspect the breather hose located under the lower manifold as they are prone to failure and can cause misfires as well. The IMT o-rings on the upper inlet manifold can also leak cause the engine to run lean.

 

Thanks NBCat. Appreciate your help.