how do you set timing for 1996 mercury mystique/?

Answer 1

More details. Did you replace the distributer? The timing belt?

Answer 2

The ignition on this engine is completely controlled by the engine management computer and can not be manually set.

There is most likely some other problem than the timing if the engine is running poorly. With today's computer controlled, fuel injected engines, there are many things that can go wrong under the hood to make the engine run poorly. Ignition timing isn't one of them.

You could throw parts at it, wasting your money, hoping you stumble on the cause of the problem.

A better solution would be to connect a scan tool to the computer diagnostic port. These scan tools are expensive, starting at a couple hundred dollars, so most shade-tree mechanics don't have them.

Some major auto parts stores will scan your engine management computer for free.

Otherwise, bring your car to a reputable mechanic and let him diagnose the problem.