When the temperature is above 75 or 80 degrees and when my 1999 Ford Ranger (4-liter V6) has been driven 20-25 miles, it has a whistle or moan at idle. I've taken the intake duct hose off the filter at idle and the noise is decidedly louder and coming from inside the intake manifold. It does not have this resonance at lower temperatures. The sound is loud enough that other drivers will turn and look at a traffic light DOES ANYONE HAVE ANY IDEA WHAT THIS IS FROM

I think I saw you post about this in the past. . . Reading the FTE forums recently, I believe I came across something on the intake that has a loud, almost unbearable whine. Not sure about the mileage / temperature aspect of it, but this is probably the IAC needing replaced or cleaning. While the car is running and making the noise, pull the connector off the IAC and if the sound goes away, you found the culprit. " Another option would be to use my "FIPK fix" where you replace the tubing that runs from the IAC to the intak with a length of 3/4" heater hose. Tends to quiet intakes down quite a bit. Let me know if you'd like more details." Check out this thread: http://www.ford-trucks.com/forums/showthread.php?s=&threadid=126329 "Mine did the same thing. Took off the IAC, cleaned it out, re-lubed it w/ WD-40 and never had the problem since. Does it sound sorta like.... WHOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOM" Hope this helps - keep us posted - Hadrian mustang347c

thanks for the help, ive tried cleaning the IAC already, maybe it just needs replaced, FOrd wants 85$ for it but if it makes that noise go away it would be well worth it

I should have mentioned this, there are people that picked them up for cheaper, maybe 30-50, you probably want to check NAPA and online sources as well. FYI mustang347c

i replaced the IAC, Problem solved....thnaks for the help

Glad to hear it! mustang347c