This is really general, i know, but i've been trying to track this problem
down for a couple of weeks now..
97 taurus GL, vulcan 3.0 engine. it's got about 160km (100,000 miles) on it.
It has an intermittent rough idle, it's more noticeable especially when the
engine is cold, or if the A/C is on. I replaced the plugs and wires, that
didn't change the condition at all. I've also noticed it sometimes takes a
few seconds longer to "catch" when cranking the engine. This leads me to
think it could be a coil issue? The car is quite well maintained as far as
scheduled service goes. I don't know if this is related, but the trans seems
to be shifting harder then it used to, the idle and the shifting seems to
have cropped up at the same time.
No codes, no check engine light, nothing. I'm just a little worried that
when the weather turns cold here (Ontario Canada) that it'll be more then
just a rough idle, and i hate doing repairs in -40 weather...