Most oxygen sensors that are replaced do not solve the problem. Moving the upstream sensors from side to side will help to eliminate the question. Also, a look at the sensor (removed) to see if it has a green stain on it will tell you if you have a coolant leak. The most common cause of coolant leak into the cylinder is from a leak in the lower intake manifold. If you do end up replacing oxygen sensors (I don't think you need to as there are lots of codes for them), use Motorcraft brand... You can get the Motorcraft sensors from
www.rockauto.com for a good price.
As always....look around for a vaccum leak.
The Isolator bolt TSB does NOT apply to the Pre-99 windstars...so do not worry about that one.