I have a 2000 Disco 2 with 123,000 miles.
Yesterday I changed the valley gasket and I thought everything was put back fine. I also changed the plug wires to STI.
Now when I start the truck, it races and idles up to 3,000 RPMs.
What did I miss??? I used the kit from AB.
Thanks

 

you got some stuff loose or you put the ignition coil bracket on top of the lower manifold or the throttle cable is completely stuck.

 

Thanks for the quick response.
I just double checked everything and everything looked tight.
The 2 top bolts for the coil bracket on the upper intake were a little loose but shouldn't the 2 lower bracket bolts be connected to the lower intake? Now the idle goes to 3500 now immediately after starting the truck.
Could this be caused by the new STI plug wires on the old spark plugs?

Thanks

 

It honestly shouldn't. Check your throttle
Cable
It should be loose. Tale off your intake tube and check that the throttle
Is closed.

 

I touched base with Disco Mike as well.
He suggested looking at the idle speed valve which was probably stuck open.
After spraying some brake parts cleaner in it, the idle is now down to 800 rpm from 2,500 after initially pushing out some smoke from the tail pipe.
However, now it pulses between 800 and 1,200 intermittently for no apparent reason. Looks like I may need a new IACV?

Thanks

 

Yep I believe advance auto has the lowest price like 40$

 

look for a vacuum leak

 

Checked for Vacuum leaks but everything looks good.
Are there any tips for checking the manifold for leaks?
Now when I give it a little gas, it will go from idling at 800rpm to 2,000 rpm. Not sure what to do now....

 

I realised that the racing was caused from the throttle body lever not returning completely closed after accelerating.
I've cleaned and cleaned but there is something just stopping to returning completely closed. If I turn the throttle lever manually, it closes all the way and the idle is normal. It's as if the springs do not have enough tension.
Before the valley gasket change, the idle was perfect.
Is this a common problem? Not sure sure what could have caused this.

 

Did you remove the manifold therefor disconnecting the throttle?

The throttle has 3 springs one on each side to keep to closed. You probably only have one. I did the same thing. Then they have a small pen spring at the bottom with hooks on both sides.