Low idle issue

[PTLimoNC]

I have a 06 LTC that is idling a little low. In park, it is about 550rpm, and when you drop it in drive (with foot on brake), it will go down to about 300-350rpm. Sometimes cuts off if you don't stay on the gas. Not skipping and not throwing any codes. Any ideas??

[MrQ45Limo]

It's most likely your Throttle position sensor

[BLVD Limo]

It may be your mass air flow sensor going bad.

[BLVD Limo]

Or it could be a clogged cat converter.

[MrQ45Limo]

Or it could be a clogged cat converter.

This is always good for starting the carpet on fire.

[MrQ45Limo]

It may be your mass air flow sensor going bad.

I would think this would throw a code

[LIMOJESS]

It could be an idler control. Those thing will not throw a code.

[BLVD Limo]

I would think this would throw a code

Not always.

Give this a try and see if it helps. Go to the bottom of a steep hill and come to a stop. Then, pedal to the metal (wide open throttle) all the way up the hill (or speed limit if reached). Try that a couple of times and see if it helps.

[Bigdan]

It could be an idler control. Those thing will not throw a code.

Absolutely, i would recomend looking at this first as Ford has had issues with their idle control motors for over 2 decades. They get clogged with carbon and it weakens them. I use seafoam on occasion to keep carbon buildup from getting bad. Also if it is running and you have the hood up and you can hear it buzzing, that is a good indicator.

[Ryan_R]

My TC was doing a funny low idle, almost wanted to die. In my case it was my EGR valve stuck open, I Unbolted it and used Seafoam Deepcreep and a q tip to reach what I could. I would try that and the same for the idle air controller valve and your throttle body, really spray the hell out of them and get that straw way in there. If neither of those buy some mass air flow sensor cleaner and carefully clean your maf with that and a q tip. If it isn't any of those the real fun begins.

[Cedar Mill Limousine]

Could be the butterfly on the throttle body too, carbon builds up so the butterfly cannot close properly. But I would put my money on either EGR, Idle Air Control, or MAF sensor. Something like this sometimes you might be better off handing it over to the dealer as what they are going to charge for diagnosis is probably going to be less than the down-time/frustration you are going to have.

[steve_b]

There is a TSB on this issue for a calibration update. Steve

[PTLimoNC]

There is a TSB on this issue for a calibration update. Steve

Steve, you are the man!! Found out from the dealership that it had never been done, so we had the calibration update done today, and this cured the problem. I usually try to stay on top of TSB's, but I missed this one. Normally, my mechanic can figure out the problem pretty quick, but this one he wasn't too sure about without some trial and error. We assumed like you guys, it was either the throttle position sensor, mass air flow sensor, or idle control valve.

THAT'S what this forum is all about. Helping each other out. Thanks everyone for the feedback! Rep for all

[steve_b]

Glad it worked out for you Jerry. All '05 thru '08 LTC are affected. BTW it is possible to do a reflash in-house, See:
http://www.motorcraftservice.com/vdi...&menuIndex1=25

I have the Mongoose, it sells for about $500 Steve