Acceleration Problem

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MCExpy10

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I was doing some searching around on the forums here and think I may have a few of the common problems our trucks have. I've been fighting with the dealership on this since we bought it (we have an extended warranty). It's a 2010 with 105,000 miles on it.

When sitting at a stoplight, you can feel the uneven motor vibrations through the car as your sitting. I think it might be a bad motor mount.

If you're at cruising speed on the freeway and you go to pass (and put your foot all the way down on the accelerator) it takes probably 3-4 full seconds to downshift and apply power. I asked about this a while back and the agreement on the forums here was to gradually put your foot down and it would start downshifting as I put my foot to the floor. That definitely helps. Cuts about a second off.

I think this is also related, under full acceleration from a dead stop, a few of the gear changes bring the truck up to "redline" and it seems like a fuel cut-off. I'm not really sure what redline is on the truck because the gauge doesn't have any markings. I assume 6500? So I'll be fully accelerating being pushed into the back of my seat, then it seems like it fuel cuts and pushes me forward (almost as if someone were to tap the brakes relatively hard), then it shifts and repeats. LOL!

I really do like this truck, but I feel like it's going to take me to the cleaners after the warranty is up... Tows like a dream though, which is why we bought it.
 

TobyU

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Isn't that a drive by wire with a electronic throttle control? GMs mess up a lot but do almost always pop a code. Sounds like that or TPS which is often built onto electronic ones is got a dead or flat spot.
 

bobmbx

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I was doing some searching around on the forums here and think I may have a few of the common problems our trucks have. I've been fighting with the dealership on this since we bought it (we have an extended warranty). It's a 2010 with 105,000 miles on it.

When sitting at a stoplight, you can feel the uneven motor vibrations through the car as your sitting. I think it might be a bad motor mount.

If you're at cruising speed on the freeway and you go to pass (and put your foot all the way down on the accelerator) it takes probably 3-4 full seconds to downshift and apply power. I asked about this a while back and the agreement on the forums here was to gradually put your foot down and it would start downshifting as I put my foot to the floor. That definitely helps. Cuts about a second off.

I think this is also related, under full acceleration from a dead stop, a few of the gear changes bring the truck up to "redline" and it seems like a fuel cut-off. I'm not really sure what redline is on the truck because the gauge doesn't have any markings. I assume 6500? So I'll be fully accelerating being pushed into the back of my seat, then it seems like it fuel cuts and pushes me forward (almost as if someone were to tap the brakes relatively hard), then it shifts and repeats. LOL!

I really do like this truck, but I feel like it's going to take me to the cleaners after the warranty is up... Tows like a dream though, which is why we bought it.
Completely reset the PCM. That will 'unlearn' the shift points and throttle maps from the previous owner. The following will help in diagnosing any issues by resetting the computer to 'default' values.

Instructions to clear and then calibrate are here:
 

rollavvti06

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Completely reset the PCM. That will 'unlearn' the shift points and throttle maps from the previous owner. The following will help in diagnosing any issues by resetting the computer to 'default' values.

Instructions to clear and then calibrate are here:


I did that on my f150 and it fixed my shifting issues...
 

TobyU

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All 3d Gen Expeditions are DBW. Since 2007.

-- Chuck
I should have guessed that since The Navigators were 03-06 fit second-generation in 07 start of the new ones. I guess the Expeditions followed the same.
Ford had that crazy thing back when the new F-150 and 250 came out that the 350 didn't come out with a new style to a couple years later.
That throttle problem sounds just like what the GM throttle bodies do when they get a flat spot. I haven't had anything 07 and up for Ford. I'm staying far away from the three valves and VCT for as long as I possibly can.
 
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MCExpy10

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Hey everyone, thanks for the replies! Sorry for the delayed response. My car is DBW. I've been told multiple times that the sluggishness of the transmission is due to my year being the first year of the drive-by-wire. Sounds like BS to me.

I might as well start with the free/cheap stuff first. It's worth noting that I have not had the transmission fluid changed. I plan on making an appointment for a transmission shop to do this and the differentials. Whatever the 100,000 mile service entails. No check engine lights in the duration I've had it (roughly 3 years, and 30,000 miles).

Problem now is that most dealerships are just parts swappers now. At least what I've dealt with so far with this thing. If the check engine light isn't on, everything is A-OK... I have an extended warranty (with a $250 deductible), but that expires in March so I'm trying to get my money's worth out of it before I'm on the hook for everything.
 
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MCExpy10

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It's also worth noting that I'm getting atrocious gas mileage. Even for our truck's already low standards. I do mostly commuting traffic, not really stop and go. I'm at a hair above 12MPG. Granted we've had a lot of weather changes around here. Not to mention winter gas.

Planning on running through this test on the TPS tomorrow, and will also try and reset my PCM.
https://easyautodiagnostics.com/ford/4.6L-5.4L/tps-diagnostic-tests-1
 

JExpedition07

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If you can feel heavy vibrations at idle it’s possible you have a misfire. They often don’t set of a CEL. At your mileage it’s worth asking because they are due. Have spark plugs and boots been changed? Both items can cause misfires at the 100k mark and cause acceleration concerns. The drive by wire can be sluggish at times on the Expeditions but it’s not because your model year. Drive by wire has been in the Expedition since the 2nd gen starting in the 2004 timeframe.
 
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