its not for me its for my girl, on her truck... drives fine i guess (a bit weak), ....the rough idle forced the heat shield to come partly off when i bought it (thats how i got it so cheap for her)....so i took it off. i can hear the muffler struggle a bit and it does chug alot when still until take off...i have no clue where the air control valve is? if anyone could give me a list of things to start with i really appreciate it... thnx

 

If it's rough like you say.. I'd start with the ignition. An inopporable IAC or exahust won't cause a roughness. They would more likely be felt as a lack of power.

Since it's used w/87k miles.. just get some new plugs & wires for it. Install them, then start the real diagnosis if the problem still exists.

Rich

 

Most likley a leaky intake gasket, a well known problem on OHV 4.0l's.

 

Id start with the plugs dudes. I had the same thing on my old ranger around that time. Changed the plugs and it ran like new again.