Rough idle | Ford Explorer Forums - Serious Explorations

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Rough idle

Joey E

March 17, 2013
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Year, Model & Trim Level
97 FORD EXPLORER 4.0 4x4
I have a 97 ford explorer 4.0 ohv 142k miles it has a 1000 rpm idle when it's idling at 1000 it doesn't bog or idle rough but when it drops to 600 it chug chug chug idle the engine rocks a little and the exhaust puffs puff I have changed the maf sensor temp sensor o2 sensors plugs and wires mastercraft egr valve and still acts up just wonderin if anyone was having this issue or know what it could be thanks

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I had the same problem for a few weeks. Turned out to be a vacuum leak. Had to replace a small elbow-shaped piece of rubber tubing and fixed the problem immediately.

While the engine is idling, lift the hood and see if you can hear a hissing sound. Mine was very pronounced.

I have searched up and down for vacuum leaks tried smokin them out tried using starter fluid just listin and nothin I haven found any but I'll keep lookin that's what I thought it was initially

I'll pull it Off and give it a cleaning and see if that helps

Well pulled it off and cleaned it and didn't o anything now it whines and makes moose calls lol it now idles at like 500 and sluggish with a power loss

IAC gasket

I would recommend replacing the IAC valve gasket or the valve itself (Idle air control valve). By replacing a bad IAC valve gasket, it can solve many different problems besides rough idling. When I replaced the gasket on my 96 explorer XLT, (with 221k miles), it fixed my idling problem and it got rid of this large humming noise that was occurring at stop signs when idling. (it can also help gas mileage :D)

This is the thread that helped me diagnose that problem (there are also a ton others):

Hi BigAG,

Could you please upload a picture of this part?