My '99 F150 4WD has started to moan very loudly at idle. Kicking the accelerator will momentarily stop the noise but it will start again after a few seconds. Seems to be associated with Mass Air Sensor but can't be certain. Any suggestions would be appreciated. It sounds like a foghorn going down the road and wakes the neighbors when I go to work in the morning.

 

That is likely an idle air control problem. If you look on the drs side of the throttle body, you will see the iac valve...a hose runs from it to a plastic box muffler...a hose runs from the box to the intake tube in front of the throttle body. Check the box and hoses... if they are OK, clean the iac.

 

Thanks, ONELOWF.

Will check it tonight.

 

NELOWF,

I pulled and cleaned the IAC and the noise went away. Just to be safe, I went and got a new one and installed it.

Thanks for the advice. It was dead on.

 

Good deal.