4.0L rough idle

[Mill1978]

My wifes 04 Mountaineer has a rough idle but no trouble codes......I changed the plugs and wires already...oh and I swapped coils just to see if the problem followed to my truck....any suggestion? Thanks

 

[EXPLORER04]

try cleaning the MAF sensor.

 

[dmohead]

look for vaccum leaks and anywhere u assume there a leak spray brake cleaner in that direction, if it sucks it in the engine will rev higher, then u'll know u have a leak otherwise check the maf, map and coolant temp sensors.

 

[dmohead]

also have someone check the fuel pressure and regulator