Got a CEL and restricted performance, so off to the garage for the diagnosis. Replaced #1 coil and plug, and now all is well again. My question is do the coils fail on a regular basis enough for me to replace the others, or should I just wait and see if another kicks the bucket at some point (if ever)? My thinking is I can get them myself (maybe through Ford) and do the rest so I don't have to worry about it happening at an inconvienient time or paying dealer prices. Any help from you guys in the field would be appreciated.

 

From what I have observed around these forums and from personal experience with my mom's LS, the coil packs can fail over time, but often more than not, they are prematurely dinged when moisture and/or oil leaks down into them. If it were me, i'd sit on replacing any others and wait for an intermittent miss/hesitation before trying to diagnose and replace any more of them.

 

agreed. I replaced one more than a year ago, and no trouble since.

 

How do you determine which one is bad?

 

the computer's stored code (read with an OBDII scanner) will tell you EXACTLY which cylinder is misfiring...it won't tell you its the coil pack though, you've got to do the investigation and troubleshooting yourself. Still, it beats nothing at all.

 

The coil packs are available at most auto parts stores.

 

Can a bad/wrong plug lead to early coil death? Or is it totally random crap-shoot if one goes?