Hey guys,
My 2000 S-Type 3.0 is approaching 134k miles soon and a new problem developed this winter. The car has a rough idle when cold and the whole car shakes when standing still. However it goes away once the car warms up.
Car revs fine above idle as well (cold or warm). I have also noticed a 5 MPG drop overall since this problem started.
Any ideas?

 

I would check a few things. What you have sounds a lot like a vacuum leak on the intake system. At the age/mileage of your vehicle, I would recommend the following if not already done:


1.) Remove intake and replace breather elbow (it rots away causing a vacuum leak).
2.) Replace upper/lower plenum gaskets while in there (they can break and cause vacuum leaks - they are a plastic cassette type with built in seals)
3.) Replace the breather pipe that goes to both valve covers and connects at the air intake boot (can be pricey)
4.) Replace any other vacuum connections that appear weak and brittle.


As long as you have the intake off, now is a good time to replace all spark plugs, coil packs, valve cover gaskets and cam timing solenoid seals.


Hope this helps.

 

Good advice there! Car's probably good for a lot more miles when fixed.

 

Vacuum leaks are more noticeable when the engine is cold since it further dilutes a rich mixture that is needed for cold starts. As things expand and the mixture leans out, it is less noticeable.


When you do this service, go ahead and check the water pump and idler bearing on the belt drive, too. Its much easier to service those items with the intake off.


Hope this helps!