Hello everyone,
i am hoping to gain some knowledge concerning my 2003 f150 5.4L lariat. i just got this truck from a relative, and i'm trying to get it running right. the truck is having a problem with slight surging in idle and most all speeds, and continues to show error code for throttle position sensor in spite of replacing 3 times with 3 different brands of sensors 2 aftermarket and 1 oem motorcraft, after resetting either by reader or battery disconnect the error code for bad tps comes back. the motorcraft tps which is currently installed tests good for voltage passing thru it as throttle is moved. once reset the check engine light usually reappears within a few minutes, along with a 2-5 rpm surge/fluctuation in idle or while driving. i first thought it was just bad from the box aftermarket parts, but since the new motorcraft one is throwing the same code i'm at a loss as to what's going on, not getting any other codes just tps. has anyone had any similar situation and or cures/fixes ? i really like this truck and i need it for work as it has become my only means of transportation, due to loss of motor in my other vehicle. i would sure appreciate any help i can get because while i'm able to drive it i'm afraid of more problems or breakdowns if this condition continues. thanks in advance to any who can shed light on this, cause i'm totally stumped.

bill

 

I would replace the IAC (idle air control) valve. Mine had a surging issue at one point and that fixed it

 

Have you cleaned the throttle body and all passages in it?

Which specific error code is it, and is it just one or several?

 

What is the code? if the TPS connector lock is broken replace it.

 

I don't know what the specific code is, I don't have a code reader, I get it read at the parts house and the mechanic I use has one. All they ever told me was it was showing the tps was bad.

 

Do you have a Multimeter? But it will be easier if you know the code.

You can also try cleaning the TPS connector and reset the PCM.

 

i do have a multimeter, but i can get the code tuesday after the holiday. the tps connector looks pretty clean but i can clean it with deoxit contact cleaner to be sure. how would i reset the pcm? will disconnecting the battery do this or do i need a code reader?

 

Check the TPS connector harness has 3 terminal. Measure the voltage between the upper terminal and lower terminal with the KEY ON, ENGINE OFF, Is it between 4.0 and 6.0 Volts.

Make sure to check your Multimeter probe resistance First.