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Cardoctor71, ASE Master Technician
Category: Ford
Satisfied Customers: 675
Experience:  MasterCertified Technician with 35 years experience, Owner of two full service repair facilities
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Expedition: I have a customer that has brought me a 2012 Ford

Customer Question

I have a customer that has brought me a 2012 Ford Expedition 5.4 with 12000 miles on it. They have taken it to several shops and dealership and no one can figure it out. The SUV runs smooth at an idle and going down the road but the problem is when you try to accelerate quickly it bogs down like you have a parachute behind it. No matter whether the engine is cold or hot or whether you are taking off or already in motion . If you lightly press the accelerator it will get up to speed but if you try and pass someone it downshifts and bogs down.The SUV has no codes in it customer stated that it has not had one since the problem started. Customer also stated that the problem started all at once while driving down the interstate. Since it has come to our shop we have replaced catalytic converters, spark plugs, plug boots, fuel pump, and cam phasers. Any suggestions would be greatly appreciated.
Submitted: 2 years ago.
Category: Ford
Customer: replied 2 years ago.
I forgot to mention we also replaced the mass air sensor.
Expert:  HDGENE replied 2 years ago.
Hello, take a look at base engine oil pressure with this amount of mileage. If it is low at idle or over 2000 rpms when hot, the vct phasers will not adjust timing properly. If the oil pressure is low you will most likely have an issue with main crank bearing/thrust washer wear. This is a common issue on the 5.4 3 valve as they get miles on them
Customer: replied 2 years ago.
oil pressure cold at idle 60 psi, hot at idle 28 psi, hot at 2000 rpm 57 psi
Expert:  HDGENE replied 2 years ago.
Ok so that sounds good, what are the fuel trims doing when the concern acts up, if they are out of sync it could point out a concern. You replaced most everything involved with timiong short of the pcm.
Expert:  HDGENE replied 2 years ago.
Post the 17 digit VIN number and ill check a few other things as well
Customer: replied 2 years ago.
VIN# ***** I will have to recheck the fuel trim and let you know what they are.
Customer: replied 2 years ago.
long term fuel trim is -4.6 short term is between -3.9 and -2.3
Expert:  HDGENE replied 2 years ago.
Ok not sure what more help I can offer at this point, im goin to open this up to the other experts and see if they can be of more assistance.
Expert:  Cardoctor71 replied 2 years ago.
does this vehicle have the original Throttle Body?
Customer: replied 2 years ago.
as far as I know yes it does
Expert:  Cardoctor71 replied 2 years ago.
the reason i asked is I have had instances where the tps in the throttle body had a flat spot, but did not fully take the sensor out of parameter so the vehicle did not set a code but engine power was reduced and sometime the vehicle would stall, it appears you have ruled out every other issue other than a failed tps in the throttle body or some type of off the wall wiring situation,or the computer itself, in situations such as these I have swapped a known good component to be able to rule it out of the diagnosis.
Customer: replied 2 years ago.
I tried swapping out the throttle body with one off of a good running truck with no change.
Expert:  Cardoctor71 replied 2 years ago.
Did you reflash the computer and test drive for at 5 miles?
Customer: replied 2 years ago.
Sorry for the delay in responding I have been in hospital. But yes has been flashed and driven more then 5 miles. We have noticed something new after driving for several miles you can smell brakes and the r.f and r.r rotors are over 350 degrees.While the left side is under 200.
Do you think it could be an brake issue causing the problem on this truck?