My 1998 F-150 has developed a squeak at 2000 rpm and higher after it rains. It is on the alternator side of the 4.2L V6 and seems to be a idler pulley or something the belt rides on. Has anyone experienced this?
Also, I put a K&N filter on and the throttle response is better and so is the gas mileage. I like my F-150 XLT. The 3rd door is great for loading my kids and guitars. Thanks!

 

I don't own a 4.2, but if you squirt water (or spit if in dire straights ---no pun intended) on the drive belt and the squeak goes away for a minute, then you know it definitely is a belt problem and, in my experience, is nothing to worry about if in good condition. If still squeaks then it could be idler bearing but should not be rain sensitive. I have found that a lot of odd noises can come from the belt or belts and squirting each will a lot of times change or eliminate the noise.

Just an idea for you.

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2000 Lariat, 5.4, 3:55 L.S., 4wd, ext cab, Tow pkg, Chestnut/Gold, Century mid-hi cap, Ford short bug deflector, contoured Ford running boards and bedmat.