I recently bought a 1999 Windstar. I knew there was a problem with the engine as the check engine light was on and the error code was a "cylinder 5 " misfire.

These are the steps take so far after researching the problem online -

replaced spark plug, checked coils, changed PCV valve, swapped injectors, compression test (it gets good compression)

We also checked other factors to see if the head gasket was bad, but there are no indications this was the case.

This is very puzzling and the guys I am working with to fix this are about out of ideas.

Anyone have any other suggestions we can try?

 

• Faulty oxygen sensor
• Faulty fuel injector
• Burned exhaust valve
• Defective computer

I've been having this problem with cylinder 2. Just happed the other day

 

You might want to check everything on the intake manifold that is over or near the #5 cylinder. Not sure what engine you have there so don't know if it uses the waste spark system. Noticed you didn't say if you switched the plug wire with another or even checked it. Did you?

 

Finally took it to the shop last week. Turns out it is a burned exhaust valve. Hoping lapping compound will do the trick. Thanks for all the tips!

 

01 Windstar had same prob. It was the coil pack-replaced and now o.k. Also changed wires and the plugs.

 

WOOHOO! Burnt exhaust valve - replaced the heads and lapping compound did the trick. It turns out that there is an exhaust leak due to some rust issues, but I will have to tackle that another day. For now I'm just glad its not a complete engine rebuild, and the engine is running smooth on all cylinders

Thanks for all the tips