View Full Version : 97 Mark VIII won't start after new plugs installed

08-15-2017, 10:25 PM
Help! I just installed new Motorcraft spark plugs (the OEM Platinum plugs it calls for) in my 97 Mark VIII and now it won't even fire when I crank it. The coils (it is a 1997 so it has coil-on-plug) all look good and seem to be firmly seated on the spark plugs and the input plugs seem OK too.

It ran fine before I changed the plugs (just changed them because they had 75k miles on them).

Thanks for any insight you can provide.

08-16-2017, 10:44 AM
Well I can't tell you much about the Mark 8, but I would look at anything in the area, where you were working, that might have been disconnected. Wiring harnesses, fuses, etc. And double check firing order from the coil.

08-16-2017, 07:25 PM
Well, it seems that the crank sensor went bad at exactly the same time I changed the plugs. So after switching plugs three times I figured it out. Ugh.