MKPatrick

Got an appt at 1PM today.
I will report back with what the service department says.

808muscle

Air fuel gauges reading only "really" matters at WOT. Its gonna bounce all over the place at idle and during normal driving. With an auto trans every time your torque converter locks/unlocks will effect the reading as well.

Now your idle issue is something else and is probably whats causing your AF to do weird things. Taking it in is the right course. Good luck.

RockStang

I just installed a Airaid Cai on my v6 and I also have weird A/F, can't wait to hear from you!

Exley

This is the experience I have to, at idle its anywhere from 13-16. My buddy who helps me tune my car said not to focus on it too much other than wide open throttle. My numbers a just a ballpark I also have a 4.6 not a 5.0.

MKPatrick

The guy at the dealership had the car all day.
He said nothing really popped out to him about why the idle is moving around like that.
He thought at first it was just the AC kicking on but I tested for that before ever even posting on the forum.
He had the same indications as I did, it fluctuates between about 600-850 rpm at idle when in park.
Sometimes the idles stumbles and it falls to around 5 for a second, then recovers and comes back up.

So he said he's sending his findings to the Ford corporation.

I got the idea that he had some sort of data that he wanted them to look at.

He said he'd call me once they got back to him.

So its not really an A/F gauge indication issue, its a fluctuating idle issue.
Anyone seen this on a newer mustang and had a positive result or new why it would happen?

M

Simon1

If its a wideband than going to MAX or off the chart on decel in gear is normal.