I own a 2009 FEH with 171k miles that has been a great vehicle. Lately I have noticed when starting out in the morning I apply pressure on the accelerator (I always do gentle accelerations) the RPM's don't increase for a few seconds, then engine "catches up" to my pressing the accelerator. I have a long driveway, about a 1000 feet, so when I stop at the end and start the accelerator is working fine and does so for the rest of the day. It does this only after sitting overnight. I have no garage so the vehicle sits outside in northern Michigan where is has been getting down to about 50-55 degrees at night.

Any ideas what is causing this?

 

I'm trying to find the throttle control arrangement for your car to make sure I'm right. It is an electronically-controlled throttle. There is a sensor assembly that actually does the "throtlling" and that assembly may be going bad.

However, it also sounds like you should start with the simplest and cheapest idea -- clean the throttle body. When you press the pedal, the sensor sends a signal that goes to the computer and then the *computer* tries to move the throttle blade with an electric motor. If the throttle body is gunked up, it's plausible to me that it might stick and move slowly at first, and then free itself up, and then stick again later.

Maybe it is sticky and not moving properly when you let it sit overnight. Are you seeing any check engine lights? Have you tried pulling codes?

 

Here is a picture showing the throttle body on a 2011 FEH, the 2009 should be similar. You'll notice that it's very similar to the one in FTM's video, flipped around. Ford's manual claims it cannot be cleaned but I call BS on that if you do what Makuloco does.

You can see how this works, basically: there is a sensor at the far end of the pedal that sends a signal to the computer which then sends a signal to the electric motor on the throtlle body to move the throttle blade and allow more air into the engine, etc.

My guess is that the TB assembly is no good, the electric motor is having problems, or it is just gunked up and sticking. Obviously you have to find it, unbolt it, get it out of there, clean it, probably put a new gasket on it, and so forth.

If that doesn't solve the problem you have an electronic/sensor issue somewhere else -- and will need something like Forscan to help diagnose it. But after all these years and miles that's where I'd start.

 

The part number for a throttle body with motor for an '09 FEH is 9L8Z-9E926-A. $39.42 on FordPartsGiant.com. Gasket is 8E5Z-9E936-A, $6.93.

 

I have noticed similar behavior on my 2007 FEH on really hot days when I first start it up in the afternoon after being parked in the sun all day. My theory is that the HV battery is too hot, is disabled by the computer, and not being used to assist the ICE. Normally, when you step on the accelerator to start moving from a stop, it’s mainly the electric traction motor providing the torque at first; if the battery is effectively disabled then you don’t get much torque. A telltale sign of this is that the charge/assist gauge barely moves while in this mode. Once the battery cooling system is given a chance to do its thing then normal operation is restored.

The Atkins ICE is inherently sluggish and slow to provide torque at slow speeds, which is why it is not used in regular ICE vehicles; only hybrids where the battery and motor can compensate.

But you mentioned cold nights and those temps don’t seem awfully cold and my 2007 seems to do fine in the cold, but hopefully this can give you some more ideas for things to look for.

 

I went to my mechanic for some normal maintenance and told him about the sticky throttle body. He sprayed it with a cleaner and now the acceleration is very smooth and responsive.

Thanks for the replies as this was an easy and inexpensive fix.

 

That's great!!! It was just a guess, but I'm glad it was a good guess and I hope it stays that way. The FEH is a "throttle by wire" car - the sensor at the end of the pedal arm, combined with the electronic throttle body, motor, reduction gearset, throttle position sensor, etc. If any of that isn't working right, grief is sure to be close behind.

Now, the interesting thing: the throtlle is all "by wire" but the transaxle and shifter are "not*. It actually uses a cable! If you ever have a shifting problem, you have to check the cable assembly!

BTW at the mileage of your car I would seriously recommend changing the fluid in the transaxle if you haven't done so: FTM shows how to do it. Make sure to use the correct fluid. Easy, fast job even DIY in the driveway. From the 2009 Owner's Manual. You will need six quarts to do it correctly. Use the genuine Motorcraft fluid, not something that claims to be compatible.

Automatic eCVT transmission fluid 5.3 quarts (5.0L) Motorcraft MERCON LV ATF4 / XT-10-QLV / MERCON LV

 

That's a good mention about the trans fluid - I had mine changed at 145k miles.

The owner manual claims you never have to change the trans fluid. (!?)

 

IMHO a legalistic euphemism, maybe a kind of dirty joke?. Some lawyer in Marketing overrode the decisions of the engineers who deliberately made the transaxle to be drained and refilled. "Life of the Vehice" expired years ago. The fluid breaks down. Why put a convenient drain and fill plug on the transaxle and say that in the manual? Ask a Ford lawyer circa 2004. The engineers at Aisin/Ford obviously expected fluid to be an occasional maintenance item but my guess is that some lawyer somewhere said: "No, no no. Tell the losers not to touch it and take it to a dealer instead, so they can spend eighteen bajillion dollars to have it diagnosed."


It's good that you changed it, I did mine at almost exactly 60k and it is running perfectly at 95k. Remember there are no solenoids or clutches in this transaxle - it's all gears, bearings and electric motors bathed in the fluid. Ford also put cooling fins on the bottom of the transaxle housing, to help keep the fluid itself cool, because it helps to cool and lubricate. If Mercon V/LV were so "durable" why put the fins on the casting when there is also a separate MECS? FTM is correct and I can vouch for it.

By the way there IS a fluid filter inside the transaxle - but you have to take it apart to get to it, and that costs real money. Avoid that problem. Change the fluid and don't let the transaxle grind itself up, clog the filter, etc., etc.

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