misfiring cylinder

[cadaverz85]

I have a CEL telling me I have a misfire in cylinder #8 on my 98 cobra. I pulled the wire off of the coil pack and no change in engine rpm or sound. I swapped the coil packs and the misfire stayed on the same cylinder, I also changed the spark plug. The wire resistance is about 130 ohms. The problem was noticed after a tune up and and computer flash with a xcal3. Not sure if the problem existed before since the CEL didnt' work before the flash. I'm not sure what to check next. Any suggestions? thanks

 

[wmburns]

Put a noid style test light on the low voltage side of the COP. This will confirm if the PCM is actually firing the COP.

The other choice is to Ohm out the wires from the COP to the PCM. IMO, much more work. Note, if the noid light does not light, the next step will be to confirm the wiring back to the PCM.

 

[trinity_gt]

If you connect the plug wire to a plug and lay it on the head so it's grounded well, do you see a spark?

If you put a long screwdriver against the #8 fuel injector and put your ear to it, do you hear it ticking?

If the answer to these two questions is "Yes, there's a spark and yes, there's ticking" then the next step is to do a compression check on #8.

 

[cadaverz85]

thanks for the advice. Will do these things then repost.