Need Help 2012 Explorer Heavy Misfires / Highway Speed

[tombynum]

Good afternoon fellow Explorer owners...

I have a rather weird problem that I'm hoping someone can help me diagnose.

Vehicle info: 2012 Explorer Limited, V6, 98,000 miles.

Throttle Position Sensor (assembly) has already been replaced.

CEL is currently storing a P0305 (cylinder 5 misfire)... but the engine runs perfectly smooth (read symptoms below)

I believe this problem is another sensor ... but I don't know which one.

Here are the Symptoms

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Regular Commuting / City Driving: Anything up 40-45 mph
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Vehicle starts perfect, idles smooth and drives great.
Commuting around town ... Runs Perfect.
Smooth acceleration, tranny shift points are perfect, silky smooth.
No Issues of any kind.

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Low to Mid Speed Highway: Anything up 45-65 mph
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Attempting to get out on the highway? Now. We start to feel some problems.
Any attempt to accelerate beyond 50 or so will result in severe lurching, feels like severe misfires.
Check Engine light may (or may not) blink for a bit.
You must give it some heavy accelerator pedal to force it to get up and go.

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Highway Cruising: Anything above 70 mph
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Once you get yourself up to highway cruising speed ... Now we're back to smooth sailing. Car will drive perfect...
Unless of course you are forced to drop back down anywhere around 60mph... then you have to give it some juice. (and you'll probably flash the check engine a few more times)

Gas Pedal ...
If your coasting above 60 mph... you can manipulate the pedal and you can feel the engine respond with lurching, misfire, etc. Agree that if feels like the TPS is whacky .. but that has already been replaced.

 

[Adrian Gitch]

If it actually is lurching even if it's only at certain speeds, it's probably not a sensor. Have your plugs been changed yet. Could be the #5 coil.

 

[blwnsmoke]

A blinking CEL can and will cause engine damage if you continue to run it. I'd strongly recommend d not "pushing through it".

I'd change your plugs (supposed to at 100k anyways) and swap coil packs and see if the code changes to a different cylinder to eliminate those 2.