I need a mechanics help-engine misfire?

my cars check engine light came on once again. before, my stepdad fixed the oxygen sensor and the light went off for about a month. i took it back to autozone the other day and they are of no help whatsoever. i have asked the same question multiple times, and get no answer. how do you fix an engine misfire?? the spark plugs have been changed, new oxygen sensor, catalytic converters are almost brand new. someone please help, thank you.



oh and the car is a 97 mercury sableI need a mechanics help-engine misfire?Might help to recheck gap on plugs and make sure no plugs have worked loose,sometimes this happens,especially if the engine was warm when installed and cools down.Also check to see plug wires are properly seated on the plugs and cap.I am assuming your car has a rotor button and distributor cap like my 96 F150. Maybe the rotor button is worn or the cap has a crack in it.Also check to see if there is any movement in the distributor shaft.If there is loose motion that could be the problem as well.My truck has 3 oxygen sensors,2 have been changed,but they never made the engine misfire.Hope this might help some.Also check your plugs to make sure one was not cracked installing.Can get brand new plugs and wires and one might be bad.I need a mechanics help-engine misfire?are you sure its a misfire?, check things like vacuum hoses, idle air valves, throttle position sensor (if applicable) go to a shop and get them to print out a %26quot;pin voltage resistance diagnostics chart%26quot; for all these items and check themI need a mechanics help-engine misfire?If you are getting a misfire code, I would change the spark plug wires.

Those wires exist in an area that has water vapor, gasoline vapor, and oil vapor and all three of those things leads to deterioration of the wires allowing electrical seepage.

This is especially it may never have been done and the car is 13 years old.I need a mechanics help-engine misfire?There are many things it can be. you may want to start with the more smaller easier things. spark plugs wires, distributor cap, rotor, check and set ignition timing if it's not set right. If the light is on you may want to find out what is setting off the light.I need a mechanics help-engine misfire?Depending on how many miles the car has the plug wires might be breaking down, if it is worse in wet weather than that is a good start. List the mils, eng size and when you notice it the most. If you pull the plugs and look close you can see if one is more reach or lean, go to spark plugs online to see how it should look.I need a mechanics help-engine misfire?a misfire is caused by so much more than just the plugs, but since you have replaced those, you are moving ahead. weak spark from a failing ignition coil, a worn distributor cap and rotor, a rich mixture or a lean mixture , a failing injector, a low compression in a cylinder. valves that dont close all the way, or seal......



a po300 is kind of tricky to resolve if you are going at it blind. you can look at the freeze frame data to see where the problem lies. this is all the information about what is going on at the point when the cpu stored that code.