Help w/ misfires

[mgreen]

I have an '06 mazda 3 hatch with about 53k miles...my CEL came on and was reading a cylinder 4 misfire. I took it to a mazda dealership and they said to replace the ignition coil for cylinder 4 so i did. about a week later the light came on again and that time i replaced all four spark plugs (they were generic and the OBD II suggested i put in factory plugs) the CEL went off right away.Today, only a week after i replaced the plugs the CEL came on AGAIN. its been flashing practically the whole time its running and its also shaking at low/idle rpms... does anyone have any ideas as to what to try/fix next???

I have already had to replace the alternator which I thought was weird with only 50k miles...this car is nothing but a headache so far!!!

 

[djltoronto]

I have an '06 mazda 3 hatch with about 53k miles...my CEL came on and was reading a cylinder 4 misfire. I took it to a mazda dealership and they said to replace the ignition coil for cylinder 4 so i did. about a week later the light came on again and that time i replaced all four spark plugs (they were generic and the OBD II suggested i put in factory plugs) the CEL went off right away.Today, only a week after i replaced the plugs the CEL came on AGAIN. its been flashing practically the whole time its running and its also shaking at low/idle rpms... does anyone have any ideas as to what to try/fix next???

I have already had to replace the alternator which I thought was weird with only 50k miles...this car is nothing but a headache so far!!!

have you had the car since new?

Why were there generic spark plugs installed instead of the OEM spark plugs before 53,000 miles?

 

[mgreen]

I bought the car in Nov. 09 and it had about 50k miles on it. It had a clean car fax and regular maintenance. I'm not sure why there were generic spark plugs....or what else the previous owner did to it.....