So not sure why it's idling around 1200. If I sit for a while it usually drops to around 800 but it's just weird. I replaced the fuel filter yesterday and ever since then. Weird. I did a complete tune up a few weeks ago. Any ideas? Is there a way to adjust the idle?

Thanks peeps.

 

Anyone anyone? :)

 

No way to adjust idle on fuel injected engines, they use an IAC(idle air control) Valve on the upper intake so computer can set stable idle

Cold engine will idle at 1,200 or so, computer is in Choke mode, this is based on ECT(engine coolant temp) sensor data, this is a two wire sensor on the lower intake near the thermostat housing.
1 wire unit, looks similar but is the temp sender for dash board gauge

Once engine warms up idle will drop down to 650-750 for manual trans

If you unhooked battery then computer needs a few drive cycles to relearn IAC Valve settings.

After engine is fully warmed up and idling, unplug the 2 wire connector on the IAV Valve.
IAC Valve will close and idle should drop down to 500rpms or so, or engine may even stall.
Either is GOOD, it means no vacuum leaks
If idle doesn't change then you have a vacuum leak

 

Thanks. Yea I did disconnect the battery. I'll see what happens.

Which one is the IAV valve?

 

This is what they look like: How to: IAC valve cleaning thread (w/pics) | Ford Explorer and Ford Ranger Forums - Serious Explorations

That's a 4.0l engine but they all look the same, upper engine near the throttle linkage

IAC Valve is just a solenoid that slides a valve open and closed, so if computer gives it 12volts it opens all the way, letting in more air so higher idle, 1,800 RPM
0 volts is closed all the way so lower idle or stall out, 500 RPM
Computer varies the voltage to hold valve at a certain place to set idle at its "target" RPM, and its vary accurate when working, 10 RPM is all it should ever vary, once engine has warmed up