99 Explorer, 4.0 SOHC, auto trans. Engine starts and runs fine, but after
it warms up the idle speed jumps around from 900 rpm to as high as 1500
rpm whether in gear or not. Can anyone help with what the problem might be
and how to fix it.
Thanks, Dennis
Vacuum leak ??? and/or
Leaking intake gaskets ??? and/or
Binding iac valve ???
C.E.L. on ????????
any codes ???????
If no codes its usually dirt related, dirty t-body and /or iac valve
> 99 Explorer, 4.0 SOHC, auto trans. Engine starts and runs fine, but after
> it warms up the idle speed jumps around from 900 rpm to as high as 1500
> rpm whether in gear or not. Can anyone help with what the problem might be
> and how to fix it.
> Thanks, Dennis
retired828 - 25 Apr 2006 07:07 GMT
The problem just started suddenly about 5 days ago. I don't have any code
info or know where to start troubleshooting to see if its a vacuum problem
or something else. I also don't know what an IAC is or where the IAC is
located on the engine. Any further help would be greatly appreciated.
Cedartown Electronics - 25 Apr 2006 18:56 GMT
IAC = idle air control .I forget EXACTLY where it is on the throttle body.
It controls the idle speed.
> The problem just started suddenly about 5 days ago. I don't have any code
> info or know where to start troubleshooting to see if its a vacuum problem
> or something else. I also don't know what an IAC is or where the IAC is
> located on the engine. Any further help would be greatly appreciated.
retired828 - 26 Apr 2006 04:35 GMT
The IAC was replaced last December by my Ford dealer. Could the new one now
be going bad or should I being looking elsewhere for the problem?
JohanB - 26 Apr 2006 06:06 GMT
Is the CHECK ENGINE light on ?????
If so, goto pepboys and have the codes read, they do it for free but don't
buy anything !!!!!!!
> The problem just started suddenly about 5 days ago. I don't have any code
> info or know where to start troubleshooting to see if its a vacuum problem
> or something else. I also don't know what an IAC is or where the IAC is
> located on the engine. Any further help would be greatly appreciated.
retired828 - 26 Apr 2006 23:52 GMT
There are no dash warning lights that come on when this happens...
JohanB - 27 Apr 2006 05:25 GMT
As stated before, no lights then its usually dirt related, clean t-body and
air idle control valve with t-body cleaner
You might have to soak the iac valve
Just GOOGLE it, for instructions
> There are no dash warning lights that come on when this happens...