Ok, I have a 99 with the 5.4l in it. It's been running rough when cold. I've put up with it for a couple years now, but as of late is getting a little worse. After reading through a bunch of posts here I'm thinking it's probably the IAC valve. I went down to the local parts store and they can get it for aprox. $50. The parts guy kinda put doubts in my head as to weather or not this would cure my problem, so I thought I would come back here for an opinion. My Expi has 61K on the odometer.

Question one: Is it most likely the IAC that is causing the problem?

Question two: At 60K should I jsut replace the thing or try cleaning it? It's clear back behind everything in the engine compartment, so I was leaning toward if I'm gonna fight getting it apart, I might as well go all the way and replace it. How often does cleaning it really work?

Any suggestions/comments would be greatly appreciated. TIA

 

I have a 99 Lariat and XLT with the 5.4. The Lariat will gunk up the IAC about every 30 to 35K miles. The XLT has the factory IAC and it about to turn over 100K. Both have a K&N filter but the XLT is subject to more severe driving conditions (farm truck). The Lariat has a few bolt on performance mods and it is driven on the street and has rarely pulled anything.

Some last and some don't. BTW I can pick up an IAC at my dealership for $36.

 

You know, mine started doing it at about 30K if I remember correctly. Well, I think I'm gonnat ry cleaning it. If that doesn't work, then I'll call the dealer here and see what they want for one. Thx