dthumper64

Hey People
I have a 99 navigator and sometimes it will just quit when i am sitting at a stop light or coming to a sudden stop.

There is also a loud humming noise from under the hood just before it quits.

5.4 lt 32 valve
4x4 all wheel drive

Thanks.

LunaticSVT

Sounds like you are having the the IAC valve(Idle Air Control Valve) issues. You can get one at an autoparts store for around $60 and replace it yourself with an 8mm wrench. It's just 2 screws and a little plug. Dealer costs to replace this would be in the neighborhood of 200$

Are you getting a CEL displayed when you experience this? If so you can take it to autozone to have them scann your PCM for any error codes for free. This will be of assistance to see if there are further issues with your SUV.

dthumper64

Thanks for the input...
I am not getting any check engine or code, I scanned it myself and there were no hard or soft faults.

LunaticSVT

I would take a look at the IAC and see if it needs to be cleaned. Usually that is the general problems I have seen causing what you are experiencing.

stang99x

X3

Its definately the IAC valve. With a little time, you can clean the inside effciantly enough to make it continue working. But, to do it, you'll need about $30 worth of cleaning agents. I would do as recomended above, and just buy a new one. I don't know about $60 bucks though, I remember it being about $120