Hey all, I have a 2012 f150 with the 3.5. lately i have been getting a bit of a rough idle, what to me is poor mileage, and a noise from under the hood, mostly at idle. I am just trying to figure out what is going on. I swear the noise is coming from the driver side turbo, but i am not sure. also it seems like low end torque and boost seem a little lacking lately. just took a trip last weekend and the highway mileage was only 17. sorry if i rambled but any help would be greatly appreciated

 

No codes pop up yet?

It sounds like maybe timing chain is in need of replacement.
My 2013 3.5 used to do the same thing. It idled okay but low boost and low power and ya some rattle noise under the hood.
It could be turbos but the turbos shut down when timing is off.

 

no codes and i did hear the rattle once last week for like 3/4 second on a cold start in the morning

 

How many miles on the truck?

Are your exhaust manifolds leaking ? How is the carbon buildup situation on the valves?

 

What do the plugs look like? I changed mine at 55k and the truck improved through the rev range.

 

Reason I say timing chain is because I went through 3 on my 2013...with similar signs as yours.

If your timing chain hasn't been replaced, its probably something you should start planning for.
Not sure how many miles you got on it.

Changing plugs is a good place to start as was mentioned. These ecoboosts eat spark plugs and its an easy cheap first step.

Maybe give it a try first.

 

yea agreed on the timing chain / phasers. probably due for replacement

 

And when replacing those plugs, be easy on the threads and make sure they get anti seize. The plugs dont have the old skule looking 4 threads like the 2V mod motors, those 595878 fine threads on the plugs need you to be nice to them!

And don't lean on the AC condensor too hard, you might crack it!

 

Um, it's actually recommended NOT to use antiseize.

 

The exhaust manifolds warp a little too easy on these trucks. I am actually in the process of getting my passenger side replaced (drivers side was replaced a couple years ago). But it is semi easy to tell if that is the issue. you will have carbon tracking, you will get a chirping sound when turbo boost is present, you can spray with soapy water when cold and see it bubble (need to do when cold or hot will evaporate water too quick), or you can do a smoke test.

Plugs might need to be changed. The 3 MAP sensors and throttle body might need changed/cleaned.