Hi,

I have a 97 Ford Ranger 4.0 XLT. The engine runs fine, but the idle sensor makes a loud humming noise when the engine has been running for a while. If I get back out on the highway and drive for a while the sound goes away, but as soon as I start to do some more around town driving the sound comes back.

Is that humming sound normal?

Does the black plastic knobbie thing on the idle sensor (where the noise is coming from) need lubricating or something?

I also wonder if it is the MAP sensor which is on the intake in line just prior to the idle sensor. The manual says that the map sensor is designed to run at a low tempeture, so I'm wondering if the warmer temps of around town driving is causing the map sensor to malfunction (?)

I'd really appreciate a clue. Otherwise I love my 2 tone XLT.

 

if u unplug the wire going to it while it is idleing and making the humm noise it will go away if it is this part. I have replaced mine and cant see that the black **** does anything. there is a possibility that u can clean the valve assembly inside. i kept my old one and cleaned it but have not tried it. the part is around $60.oo . later alan

 

Hi slater8, welcome to FTE!

You should probably read through these recent threads:

Ranger IAC Noise1

Ranger IAC Noise2

 

Thanks Alancp for the tip. Based on your post and some others I will try cleaning the idle sensor and if that doesn't work I'll just replace it.