96mercury villager when it was put on the code reader the code said the knock sensor was bad. What else would?

"The knock sensor responds to spark knock caused by Pre-detonation of the Air/Fuel mixture."

You are most likely in need of a tune-up. This consists of spark plugs, spark plug wires, distributor cap, and distributor rotor.

Other causes of misfires could be, but not limited to: engine timing off, ignition timing off, low compression, faulty or failing ignition components (coil, distributor, etc), and fouled spark plugs.

The type of fouling can represent one or multiple problems. EXs:

-Regular wear, symptoms: rounded electrode, causes hard starting, and causes poor economy; solution: plugs have been left in engine too long, replace with plugs of the same heat range.

-Oil Deposits, symptoms: oily coating caused by poor oil control, oil leaking past worn valve guides and/or piston rings, solution: correct the problem with necessary repairs and replace plugs.

-carbon deposits, symptoms: dry sooty deposits indicate a rich air-fuel mixture, weak ignition, low compression, and causes hard starting, misfiring, and hesitation while accelerating; solution: make sure plug has correct heat range, check for a clogged air filter, check for fuel system and engine management problems, check for ignition problems, and check compression, and replace plugs.

I have news for you: The anti-knock sensor NEVER causes the engine not to run. Stay away from Auto Zone! They're not mechanics. Their $29.55 tea-leaf readers are not able pin-point specific emissions issues accurately.

A trusted private mechanic or Ford dealership should check your idle air control valve. NAPA and Car-Quest has them for a lot less money than a Ford Dealership. This is not to say your EGR valve may be sticking open.

This device is an digital sensor which detects the position of the crankshaft, it really works together with the EFI and distributor to send the spark at the special time to every cylinder. In case your engine continues to be running easily then it could be a false alarm.

if it said knock sensor have you replaced it