Strange strange acceleration problem

[yoster]

2006 v8 explorer EB 4x4

Hello,

So I have this really strange issue going on with my Explorer. It's still under warranty but I'd like to have an idea about what it could be before taking it in because it's definitely one of those things where they could say "well, it didn't happen when i drove it!"

So I'm leaving for work, start the truck up for the first time all day; 7am. If I get in it and take right off at anything but a VERY slow speed, the thing bucks like CRAZY. Like RPM, 800-1500-800-1500 instantly. ROMP ROMP ROMP. It happens after it sits for awhile, and only when you're going for the first time. It almost got me in the wreck last week at the boat launch. We came in and I went up the ramp to get the truck and trailer. Started it up, went to pull out of the stall with the trailer and it did that almost sending me into another vehicle.

After the first take-off, it's fine. But even in normal driving, the acceleration is not smooth. It kind of pulses as you accelerate, unless you're either putting along at the speed of smell, or flooring it. Normal or brisk acceleration results in this pulsing sensation. Sometimes very hisitant, but it's always there. It's just VERY bad (and dangerous) in the mornings/after it has been sitting. Happens when I'm leaving work too. I have to take off, then stop and let it sit idling for about 10 seconds before I can go without it doing it.

Ideas?

 

[NCcarguy]

My guess is one of two things, and both can be taken care of at the same time. The "Throttle position sensor" is bad and needs replacing and the Throttle body needs cleaning. The TPS is located on the side of the throttle body, so the throttle body should come off anyway, why not clean it.

 

[yoster]

If the TPS was the culprit though, why would act so much worse after the car is first started? Same goes for cleaning the throttle body; I'd imagine that would result in a constant symptom, not one that's REALLY bad on initial start-up then gets better afterwords.

Perhaps the ECU does some type of correction after it detects the strange TPS readings when I first start out, then it gets a bit better until I turn the truck off again and let it sit?

 

[ZO6_Vette]

Could be an ignition miss, take a spray bottle and with the engine running spray the coil pack and see if the engine runs rough or electric leakage.

 

[MrQ]

IAC? I don't know if they still came on the new SOHC's.

 

[belvin20]

My 06, V-8 had the same problem, throttle body was replaced, there is a Ford TSB for the problem and the dealer should be aware of the problem. As I recall, there is a computer re-flash when mine was repaired.

 

[yoster]

Thanks!! Do you know what the TSB is by chance? Just took it in today.

 

[Rngrs3910]

I'm having a very similar problem, except its pretty constant, doesn't go away after driving for a while, and there is no sign of in on my tachometer, just the sensation. The guy I take mine to orginally thought throttle body, reprogrammed it and the problem went away for a month. It recently came back, same symptoms, but now my mechanic can't find any problems.

NCcarguy - was your v8 throwing any codes or was the C.E.L. flashing?

 

[yoster]

Hello everyone,

a quick update. Of COURSE Ford said they "couldn't reproduce the problem" - I honestly don't even believe they tested the vehicle because it's pretty obvious. They told me it's "gear stacking" and is normal? What in the world is that? Gear stacking??? I tried to insist that this is NOT normal; they wouldn't listen. And of COURSE, the vehicle is out of the full warranty now; just the basic CPO powertrain warranty at this point. They also charge me $50 bucks each time I take it down there, unless they find an issue. How can I MAKE them see this issue? Frustrating.

 

[willied]

Hello everyone,

a quick update. Of COURSE Ford said they "couldn't reproduce the problem" - I honestly don't even believe they tested the vehicle because it's pretty obvious. They told me it's "gear stacking" and is normal? What in the world is that? Gear stacking??? I tried to insist that this is NOT normal; they wouldn't listen. And of COURSE, the vehicle is out of the full warranty now; just the basic CPO powertrain warranty at this point. They also charge me $50 bucks each time I take it down there, unless they find an issue. How can I MAKE them see this issue? Frustrating.

Go out in the car with them. That way they can't deny it if it's happening when you're in it.