Idle problems

[gerald holland]

I have the 2000 Expedition with the small v-8. A few weeks ago the idle speed started wavering after I would slow down at a stop. It will rise and fall about 4 times and then it will steady out and be fine. Until the next time I came to a stop. Sometimes it will fall so far the engine will stall. I then start the engine and the idle speed is fine, until the next stop. I need help on this one.

 

[AZShawn]

Unfortunately this is a tough one, because it could be many things. Check all your vacuum lines first. Sometimes rubber boots split or become too weak and cave in under vacuum, or the hard plastic lines crack. Check the bigger hose at the very back of the intake, towards the firewall.
If you have a code reader, see if it is throwing any codes that can point you in the right direction. Could be IAC, EGR, maybe coil packs or spark plugs, etc.

I know the frustration of searching for causes of a rough idle, I wish you luck!

 

[gerald holland]

Thanks. I replaced the IAC and no change. I will try everything. Thanks, Jerry

 

[Yupster Dog]

Why do you have three threads going about the same thing?
Refer all post to the one so everyone is not posting the same thing in different threads.
People want to help but not when you make it harder.