99 4.0 SOHC Rough idle that smooths out with a little gas

[blue89bird]

4.0 SOHC with 128k on it.

Occasionally the idle is a bit rough. I noticed that if I keep the tach at about 900-1000, then it completely smooths itself out.

I was thinking dirty IAC but before I go and pull it off I was looking for suggestions.

 

[my98nnj]

Were the plugs ever replaced? It's a goog idea to clean the throttle body and icv, maybe run a bottle of Techron through the fuel system as well.

 

[blue89bird]

Should have mentioned that. Previous owner had plugs/wires replaced a few months back.