Hi everyone. I just picked up a new to me 02 Ford Excursion. I have wanted one of these since first seeing them but being in construction and needing drw trucks up until now had prevented me from getting one. After a shoulder injury and surgery my vehicle needs have changed and I was fortunate to find a clean 02 with the v10 which is something I am not at all familiar with. The deal was too good to pass up. It has a 6" suspension lift, 35x12.50-18 tires, and plenty of room for my family. It did however have a few minor issues. The first was as simple as replacing a fuse and hooking the front differential vacuum hose up to repair the 4x4. The second is giving me a little more trouble. It has a high idle that seems to get worse as the engine warms up. I initially checked for any vacuum leaks since I found the hose off of the front differential but have found no other leaks. I have heard that it could be the IAC valve or possibly the maf sensor needs cleaning. I can't tell for sure because its so clean under the hood but it appears that the fb or at least the sensor on it is new but I haven't removed to inspect at this time. The truck also has open exhaust with no converters or mufflers which I intend to change. I wasn't sure if this could be an o2 sensor issue because of a lack of back pressure or improper sensor reading issues. Any ideas or help resolving this issue is much appreciated. The truck runs excellent and doesn't skip or surge, it just idles higher than normal at times. Thanks in advance.

 

Might want to check the butterfly in the throttle body to see if it is sticking and not closing all the way.

 

check the pcv elbow under the throttle body. It's kind of hard to get to, I pulled the throttle cable bracket to get a better run at it. The IAC is a bitch to get to, you have to super man across the engine compartment to pull the two bolts, try to save the gasket I think you can clean and lube rather than buy new. I had a split on the pcv elbow that was causing my idle issues. 2000 f250 v10

 

Your issue sounds just like a vacuum leak. As mentioned about about the PCV elbow, its really common. A good place to start