I just purchased an 01 gt convertible. Within a day of driving it, I parked it then cranked it, and a CIL came on. Then next day I scanned it and the code said Cylinder 8 misfire detected. I then purchased 8 new accell coils and motorcraft platinum spark plugs and installed them. I started the car and ran it without any problem. the next day, I drove the car without any problem until midday. I parked the car for about 15 min then went to crank it and it didnt start the first two turns of the switch. the third time it cranked and ran fine. i then bought a fuel filter and parked the car. I then cranked it, and while idling the CIL came on again. Does anyone out there know if theres a problem with this specific vehicle to cause number 8 to misfire aside from coils or plugs. The car runs great with no hesitation or rough idling. The car does idle low however around 500 RPMs in drive with no A/C on. The next step is replacing the injector on Cylinder 8. Any reply would be appreciated.

 

There are many different reasons for a misfire on a specific cylinder. Not getting (adequate) spark, fuel, compression or air. Timing is off (although that would cause multiple cylinders to misfire). Start by getting a spark tester and make sure you are not just getting spark, but enough spark. If not, then its an ignition problem (e.g. bad wire/connection). After that, rent a noir light kit from your local auto parts store and test if the cyl 8 fuel injector is being commanded on when it is supposed to. If it is, rent a compression tester and make sure your getting roughly equivalent pressure on all cylinders.

Good luck...