2000 bone stock S/cab, 4.0 ohv with a 5 spd. auto., 77K miles

At times, after a long period of deceleration the engine will run rough, barely idle @ 400-500 rpm, like it's loading up. Bringing up the revs will clear it up.

The MIL light does not come on, indeed my code reader indicates no problem codes at all stored in the ECU.

Plugs and plug wires are new (Motorcraft platinums),both the throttle body and IAC are clean. Yes, the air filter is clean, fuel filter was replaced 5K ago.

Haven't checked the MAF yet, suspect the problem may be with it, and/or O2 sensor(s), thing is no codes are being displayed.

And..., this problem is intermittent

Anyone have a clue?

 

Mine was doing this when I would come to a quick stop or put my foot in the clutch or put it in neutral and the RPMs would drop from 3000k+. When the tach dropped it would go all the way down to 500-700RPM and the truck would act like it wanted to stall then it would even back out at idle speed or I would tape the gas pedal.

To fix it I just used the adjuster screw on the throttle body that controls idle on the throttle cable mount. I cranked the bolt like 2 turns and problem solved. No my idle never drops below 700RPMs.

 

Also go ahead and get some electronic/MAF cleaner and clean it up, couldn't hurt.