My 98 Taurus started misfiring and Idling rough when stopped in park
and reverse. Also Tachometer is intermittently dropping to zero when
engine is running. These symptoms appeared right after I took the car
to the dealer for a 100k mile spark plug change and transmission
flush. Also got a new fuel filter so it aint that.
I pulled the plugs and they all had a light cocoa colored coating on
them except the one at the rear on the passenger side. It was dark and
didn't look oily, just no coating like the others. My next planned
step was to shotgun it with new plug wires and and a coil module.
I don't want to go back to the dealer again, seems like they are just
guessing like me most of the time but charging $$$$ for labor and high
markup parts anyway.