Originally Posted by gotaford
they called ford and ford said they have never seen a malfunction of this device. 650.00 part that sits on the fuel rail.
Someone is BSing you. The 99~00 Ranger Flex Fuel Composition Sensor has a fairly high mortality rate. So much so that there is at least one company
is making an replicator to replace it. (The replicator is set up for unleaded gasoline with no morre than 10% ethanol. After installing it, the vehicle would no longer have Flex Fuel capability which had originally allowed up to 85% ethanol.)
The sensor is not mounted on the engine fuel rail. It is in the fuel line down near the left frame rail.
You may well have a problem with the oxygen sensor but I would get the problem with the Flex Fuel Sensor resolved first before attempting to fix it. Getting the mixture straightened out MIGHT take care of both issues.