a couple months ago my 2002 4.0L starting acting like it had a bad IAC .... dropping RPM"S at idle ... I had this happen to it once before ... it would idle fine then drop 100 rpm or so and back smooth ..... I cleaned it before and then cleared it up ... then it started again .... cleaned it and no help .... so I took it to a garage and he cleaned the MAF and IAC too ... then when I got it back it was idling different ... it was like it was loading up and surging ... so I take it back and he changes the fuel filter and spark plugs and said I had the wrong plugs in it ... they were too short and he puts in Autolites .... and he raised the idle ..... but it still was idling bad... so I put a new IAC in and still no help .... then I get some bosch plus's and put in (same as I had in it before and it ran fine for 25,000 miles) still no help ...... running out of ideas ... it has 112,000 miles ... gas mileage seems fine .... just ruff at idle .....
so does anyne have any idea's as where to look next ? Thanks