Scot

Hello all. I am new to the forums. Recently purchased a 2004 Screw 5.4L Lariat edition with 24,000 miles. Noticed that when dropping the pedal to the floor the truck falls flat on its face and resumes expected acceleration after a 1/2 second or so. I havent been able to find a previously posted thread describing this symptom and was hoping yalls could shed some light on it.

wde3477

"Doctor, it hurts when I do this."
"Then quit doing that."

Ah, but seriously - has the 'check engine' lamp come on? May be a good idea to see if there are any codes stored. Also, assuming here that this is a problem with the engine gagging, and not with something like the transmission not downshifting?

Perhaps the MAF sensor needs cleaning?

tonkatruck66

off topic, whats an MAF sensor? just wondering...

and hope you find out what the problem is scot

05 super

mass airflow its a sensor located just after your air intake.

Buck

This "falling on its face" for a split second before hard exceleration is a byproduct of the electronic drive system these trucks have on them. You see, older vehicles have a drive by wire setup (the throttle is connected to a cable that manually controls the fuel/air input into the carb or throttle body. This newer system our trucks have is all electronic therefore no wires. This hesitation you are experiencing is the computer taking that split second to realize that you have infact put the petal to the metal and then sending the signal shortly after. From what I have heard this problem can be taken care of pretty good when you get a tuner. Otherwise I think its just one of those things your going to have to deal with. Ford may have an updated program they could upload onto your computer. But Until you get a tuner I believe u will always have this hesitation as a byproduct of not having the direct cable link to the throttle body. Hope this helps

P.S. this problem may potentially be magnified by such things as a dirty MAF or other minor things. But my truck does the same thing. I am planning on eventually getting a tuner so hopefully this will help with the hesitation.

Also, I may be off on this so other more tech savvy members feel free to ring in

tonkatruck66

oh, DUH. haha, i knew that just having a stupid moment.

Scot

Not to be a jerk and sorry if it comes off like that but "Drive by Wire" actually means that the throttle is electronic and pertains to mostly new vehicles. The "Wire" portion of it is the electronic part. Term came from Aircraft technology "Fly by Wire" where instead of using braided cables to mechanically move the flight controls, it sends electronic signals to munipulate Hydraulic servo actuators. We dont have Hydraulics, but the electronic logic of it is the same. Again, not trying to be a %$#@. Thus far I have reset the TPS (Credit to WhiteCrystal) and it seems to have cut the hesitation in half. With the help of this forum I have determined it normal and a tuner to be only anadote. Thanks for all your help.

Buck

haha my bad. I had heard the drive by wire thing in association with topics like this. I just got it mixed up apparently...I have seen several topics on this subject not only on this forum but others....maybe a search would yield more info for you...

Scot

Cool, you took that well. Again, its so hard to reply on paper and not come off sounding like a jerk. You said yours does the same thing? What year and how many miles does yours have. I know its not that big of a deal but when you pay that kind of many for something you want it to perform like its worth that much. Just verifying that its normal cause I bought it 3 weeks ago and with it being an 04, its 3 year warranty is up. You need all the piece of mind you can get when you walk away with a used truck from the stealer.

Buck

Ya mine is an 04 as well. The severity of the hesitation depends on the quickness I put it to the floor. If I slam it to the floor it hesitates noticeably but after that it takes off like a bat out of hell. Everyone I have seen having this problem has been explained to that it is in fact due to the electronic throttle. It has to send the signal to the computer and then it has to engage, whereas a direct cable has little to no hesitation for obvious reasons. From what I hear we either need to accelerate a bit slower and deal with with the hesitation when we gun it, or buy a tuner. Supposedly the tuner helps get rid of a lot of the hesitation. I plan on going the tuner route since I plan on eventually getting an exhaust and intake in the future any way.

P.S. I know what u mean about trying not to sound like an *** in writing, no worries though, I consider myself smart but Im far from a mechanic and stuff often gets lost in translation ....I knew it had something to do with the "drive by wire" deal one way or another

...even though you ended up correcting me I hope I have been somewhat of a help.