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2112 F 150 XLT Ecoboost
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Discussion Starter · #1 ·
I just bought a 2012 f150 XLT Ecoboost with 70,000 miles on it.
when I test drove it I never floored it, well today which is about a month later I decided to. And when I did it started accelerating to about 60 miles an hour but then it wouldn’t go any faster and the rpm needle was jumping around 4000 rpms. Can any please point me in the right direction, I’m so worried that I just bought a lemon. Thanks in advance.
 

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Discussion Starter · #4 ·
Thanks guys. I will check into what each of you said.
 

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Discussion Starter · #5 ·
There's so many things that it could be. These are pretty sophisticated motors, and they are awesome when operating properly, but any truck with this motor that is beyond the powertrain warranty really needs a thorough shakedown before signing on the dotted line.

I know it's too late, but it would be prudent to find someone who knows these motors specifically and have them do a thorough Pre-purchase Inspection on it. Or at least get the truck up on a lift and give it a thorough look under every nook and cranny with a bright light. Also get a real diagnostic tool hooked to the ODB and pull any and all codes.

The most common issues are all addressable, of course, but a few of them are labor intensive so they can be costly.
Just a thought, but do you think it could be a spark plug issue? I would think if it was something big that my check engine light would have came on by now. But I am going to go get the codes read tomorrow if there are any
 

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Discussion Starter · #7 ·
Let's just say that if you are going to take the process of elimination strategy, and considering the history of the 3.5 Ecoboost, AND you are intending to keep the truck anyway, then this would be the first things I would do. (but I would pull those codes no matter what because they just might have some valuable clues)

Fresh plugs gapped about .28
The boots are cheap and you are in there anyway, so boots too
Fresh air filter
Fresh oil and Motorcraft filter
And because it is relatively inexpensive AND a malfunctioning one can cause the craziest symptoms, an oem throttle body. (easy to change too)

Because it is a 2012, I would make sure that you don't have an Intercooler with a big build up of nasty liquid laying in the bottom of it. (either drill a hole in the bottom, or if that makes you queasy pull it and dump it if it has any liquid in it.

You also should take a really patient look around for broken or damaged vacuum lines. Your truck is very dependant on vacuum for a lot of things that affect performance.

Then take it out and get everything good and warm before you roll into a WOT pull.
It would be nice to have some method of monitoring some pids via your ODB port, but you can wait until you verify that the list above made a substantial impact.

You didn't mention any alarming noises, so I'm assuming there wasn't?
No sir no alarming noises at all, I never suspected any issues due to no noises and no check engine light, but now I see I have a lot to learn. Thank you sir for taking your time out of your day, I really appreciate it.
 

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Discussion Starter · #10 ·
Why 4K rpm? Did it shift? Did it shift when you let up on the throttle? With the tachometer fluctuations it could be a misfire. Check the easy stuff. Mouse nest in air box? Spark plugs‘ condition, gap, color. Fuel fresh, water contamination? 2012 with 70K miles it could be suffering from many conditions associated with long term storage.
Yes it shift, it’s like when I floor it get stuck at like 60 and if I keep it floored after 60 the rpms will bounce around 4K but it won’t go any faster, but if I press the gas aggressively without flooring it it runs like it should.
 

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Discussion Starter · #12 ·
Wait, I didn't realize it runs normal with aggressive throttle but only acts weird at WOT.
That's a very different and specific situation.

I'm back to suspecting Throttle Body and/or Throttle Position Sensor. I think you can do a recalibration of your Throttle Position Sensor.
Yes sir, I’m going to get the codes read today after I get off work and if everything checks out on that end I’m gonna get a new throttle body, spark plugs and boots. And see where that takes me
 

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Discussion Starter · #17 ·
Ok so I’m getting the boots and plugs done next weekend, I will let y’all know what happens, but now I have another question. I really think I may have messed up. While looking at everything I realized that the coolant level was low in the reservoir, so I went to Napa asked them what I needed and they sold me the extended life universal 50/50 mix coolant, so I put about a quart or so in it, then I noticed it said on the reservoir it needed orange motorcraft coolant. The coolant Napa sold me says it can be added to any color and like I said I only put about a quart in it. Do y’all think I need to have it flushed or do you think I’ll be fine?
 
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