I had the same problem on my 08 Limited 5.4 when I bought it 2 months ago. Here's what I did to fix the problem. Turn the key to the on position but DON'T start the engine. Now press the gas peddle to the floor SLOWLY and let it come up/back as fast as you can, turn key to the off position. Now do this two more times. Now start the engine and go for a test drive then report back here with your findings!
This procedure works on my motorcycle so I tried it on my truck and it worked there too!
I also disconnected my battery but that was a couple of days later and wasn't done to correct the throttle problem but it drives like it's suppose to now.
I wish they would make a "STICKY" about this procedure, there are so many people that are saying this and saying that about what if will do and what it won't do....here are the facts:
If your vehicle has throttle lag and it doesn't matter if it's with wire or without wire this procedure will fix the lag, it will fix any throttle body TPS scale 0 - 100% on all fuel injected vehicles. If you don't have the lag then it does nothing for you but if you still do it, it will not hurt nothing and if it does then you already had something wrong with your vehicle.
*Put key in the ignition and turn to the "ON POSITION" do not start motor!
If you did accidently start the motor just cut it off and start over...no big deal!
Key to "ON POSITION"
Wait for the chimes(bells/whisles to stop) then press the pedal to the floor slowly, once you hit the floorboard let the pedal back up quickly, now turn the key to the "OFF POSITION". Now you can do this procedure two more times or you can start the motor and go for a ride and see if it fix the lag, if it didn't try doing it again but do this procedure a total of three time before starting the motor and going for a ride.*
I have done this procedure to motorcycles/cars and trucks.....on a motorcycle Kill switch in "OFF POSITION" "key to "ON POSITION" Now switch the Kill switch to "ON POSITION" ,Now rotate the throttle to full open and quickly return to closed.....switch kill switch to off and turn key to off, now do this two more times and you're ready to ride.
These are some links i thought might be useful.
If you have any other links regaurding the throttle lag, post them and i will add them.
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