Intermittent loss of power

[clawfootMKS]

Context:
I got a 2010 MKS 3.5 last november and it's been great! Family friend owned it, all work done at the dealership including PTU replacement, turbo replacement, oil pump replacement. All done through a Lincoln Dealer in MI (minus the PTU which was done in Ohio from a Ford Dealership). 155k Miles

It's not heavily modified or barely modified at all.. Airraid Intake, and Livernoise 93 Octane tune.

I've noticed for the past 4-5 weeks that SOMETIMES it seems like it cannot get out of it's own way. Mainly after it's warmed up. Throttle feels really slow to respond and it just doesn't pull as it did when I first drove it prior to buying it. Radiator fan also sometimes kicks on high when i'm idling. First noticed the lack of power when I went to reverse and it couldn't move itself a little without my hitting the gas.

I have taken it to the Lincoln Dealer who did the turbo replacement, they said they couldn't find anything, turbos appeared fine and that my fan running hard is normal if I have my heat on. Also took it to a local mechanic twice and they said they couldn't notice anything that stuck out to them. Both parties suggested it's just getting up there in mileage.

I've spent the past 2 days looking at posts and couldn't find the same problems but please link me to any threads.
Just looking for some advice on where to start. - A friend of mine said it could need a valve cleaning and timing chain replacement (mini-rattle sometimes on cold starts)

 

[Ta2dResqr]

Do you have a scan tool/code reader? Can you see what kind of boost it is making? May have a large leak somewhere (coupler popped loose, plastic tubing burst, etc.) Does it feel like normal sometimes and no power other times? Any check engine lights?

 

[clawfootMKS]

Thanks for the response!
No CEL ot DTC codes. I have the livernois device that came with the car when I bought it so I'll check the boost levels on my way home this afternoon. It certainly sometimes runs fine but lately you can feel how sluggish and off it feels.. becoming more common. Boost leak seems plausible because of the continuing decline.

 

[VwCSilent]

Hope the problem was fixed. If not, some of the 3.5l have a throttle body issue. The butterfly will only partially open. This is the case on the regular Taurus but I think the sho uses a different throttle body so the mks might be different also. In the one case I personally saw, no dtc was given.

 

[SHOdded]

check for chafing knock sensor wiring also. have you tried putting it back to stock?

 

[clawfootMKS]

Was out of town for a few days.
As far as how much boost it's making - from the info I found using the myCalibration device with the LMS tune, Boost would be the MAP reading divided by like 2.036 which came out to 21 (20.83). Map reading hit 42.42 around 4500RPMs.

I'll locate the Knock sensor and see if I can see any chafing.

Is there a way I can also check if my throttle body is not functioning correctly? I have done a throttle reset procedure in the past and it felt like sometimes that would fix it short term but not sure if it's true or a placebo.

Thanks everyone for your input.

 

[VwCSilent]

Will that device show stored codes or only current ones?

For the throttle body, I had described the symptoms to a Ford mechanic and he suggested throttle body. Said he has replaced a ton of them. The car drove normally most of the time but every now and then it would act like it was ignoring the pedal. It would limit you to like 5 mph. It would randomly happen while driving. Sometimes turning the car off and back on would fix it. Sometimes not. The last time it happened it almost killed me on i95.

Replacement throttle body fixed it. Maybe $100 on rock auto

Hopefully someone with more experience can chime in and fixed what my explanation ******.

 

[SHOdded]

if you check the throttle body and find gunk on the plate, check the intercooler for fuel/water buildup. if you find such buildup, vacuum it out. it will definitely smooth out performance. most times the tb on a sho/mks has not been a problem, there have been a couple of cases tho where it had to be replaced.

you can check etc_act vs etc_dsd and that will tell you if the throttle body is accurately reacting to the pcm commands.