Just did a tuneup new wires and plugs how do I

I don't think you really understand what this fault code means, it means that likely all the engine cylinders are misfiring at random no set pattern, not any particular cylinder. I would start with checking for engine vacuum leaks like the intake manifold gasket. that is all I can say since you provided no make, model or year and engine type and size information.

try disconnecting the battery for 2 minutes.....the computer usually resets itself and will usually turn off the "check engine" light

DO SPARK PLUGS AND WIRES CHANGE IF NOT HAVE DONE TUNE UP IN A LONG WHILE. CLEAN FUEL INJECTORS.CLOGGED FUEL INJECTORS WILL CAUSE CYLINDER MISFIRE ALSO.

The check engine light doesn't have to come on with a bad crank sensor ,your vehicle has two , one for lower rpm an one for higher speeds . A&B
The two crankshaft sensors are located on the front bank (BANK 2) of the engine block between cylinders 4 and 6. Crankshaft position A sensor is located in the upper crankcase and crankshaft position B sensor is located in the lower crankcase. Both sensors extend into the crankcase and are sealed to the engine block with O-rings. The crankshaft position sensors are not adjustable.

There isn't much to a tuneup now days, I wouldn't even bother with plugs and wires unless it needed it. The basic tune up is an oil change, air filter, check all fluids, brake pads, hoses, any thing that needs attention. I don't think I have changed plugs in 10 years, or wires for that matter. And I am driving a 94. Hope this helps.

fuel filter (supposed to be done every 30,000 miles), transmission fluid, coolant, p/s fluid, brake fluid, spark plugs, spark plug wires, check timing belt.. those are things recommended by gm after 100,000 miles

the plugs are under the wires that go from the distributor to the engine.

random misfire does the engine have lack of power or a miss... sounds like maybe bad coil pack......wire.....or plug do good tune up see what happens let me know if more help needed

"service soon" is a reminder that it needs regular maintenance, and usually the dealer has a tool to reset that light on the dashboard, which can be expensive to buy.

If you do all the maint yourself, and you know that all the fluids have been replaced or capped off, you could cover the light with a piece of black electrical tape, then go on with your life.

mechanic probably broke a vacuum line, or vacuum connector while "tunning up" your mitsu. also check for loose plug wires or plug wires that come very close to exhaust manifold as they may be tight and look new but are brittle and broken on the inside.