That annoying groan is back. Seems to do it until the truck has been driven for a bit then it goes away. Only does it when going slow (speeds 10 or less) and when slowing down. Does it with or without brakes being applied.

Wish it would do it when I take it to the dealership but it never does....

 

I was staring at this trying to understand what you were saying, I think you meant groan. But anyway, where is the groan coming from?

 

Is your truck an eco boost? If so it's the vacuum pump and if that's not it is your 4x4 in gaged? If so it's the 4x4 actuators.

 

Yep, groan. Damn autocorrect.

From the front end somewhere

 

Yes it's an ecoboost, it's in my sig line.

It makes the noise with or without the 4wd engaged. Vacuum pump? How could I check that

 

I just looked up the vacuum pump video. That buzzing noise that it makes is not the same noise. I do hear that buzzing noise for 10 seconds or so when first starting the truck.

 

I get the same noise on my 5.0, when it's really cold outside and I'm waiting at a light is when I really here it. After the truck warms up it goes away.

 

I started hearing this same noise once the temperature dropped. The noise only happens after the truck sits for a while (2+ hours) or when the truck is in 2wd. Once the truck is warmed up or if I engage 4wd, the noise disappears.

I just dropped the truck off at my local dealer a 2nd time for this noise. Told them to hold onto the truck until they can replicate the noise.

 

Please let me know what they find. I have a sneaking suspicion its IWE related. Moisture in the line?

 

On the first visit to the dealership, the tech tested the vacuum lines and visually inspected the IWEs. Nothing was out of the ordinary. Everything the tech saw was operating normally. This is of course after he took the truck out for a test drive and warmed everything up.

When I dropped the truck off this morning, I was speaking with one of the techs that was filling in for my service adviser. I asked the question if moisture would pose an issue in the vacuum lines. He stated it is quite possible. Seeing as though this issue only arises after an over night soak and the temperature change. The fact that once the lines are warm, the issue disappears is a good indication that lines may have something in them.

I will certainly keep you posted on my results.