'08 King Ranch really this slow?

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Adieu

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Well if it dont rev properly, go buy new plugs, new air filter, maf cleaner, and throttle body cleaner.

That's a hundred bucks total, WITH BEER.
 
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34Ford

34Ford

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What was I thinking. It will not rev past 3k in neutral, it has a rev limiter.

Anyway, I have new plugs, new K&N CIA, cleaned the ma sensor and a brand new throttle body with iac and throttle motor.

Fuel filter was changed at 24k now has 124k so buying a new one this evening.
 

coolzzy

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Have you replaced the coil packs? They can behave differently when hot if they have hair line cracks which can cause internal issues to the coil pack as the plastic bits slightly expand with heat. Bad cops don't always throw a code or cause poor idle. You can buy a replacement set of non oem ones on ebay for around 100 bucks and they are relatively easy to swap out. Did you use Motorcraft spark plugs? If not, swap those out asap and return to the stock ford plug since they will run best regardless of what the aftermarket brands might claim or advertise.
 
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Yes, Motorcraft plugs. Changed fuel filter last week. Bought a fuel pressure gage yesterday.

Haven't considered the coils yet. Will start looking.
 
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I bought a SCT X4 tuner and just tried a 87 octane tune and WOW it woke this lead sled up a lot. Can't wait to try 93 octane tune.
I am impressed.
 

1955moose

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I can't believe 45 posts later and you haven't done a fuel pressure test, and checked exaust for back pressure ! Screw a gauge into front o2 sensors and see reading. The reason it ran better with a tune is they fattened up the mixture and advanced the timing curve. I still can't believe you bought it this way, without having them fix it first. What if your motor had been shot, bad valve, rings. Do the 2 things I mentioned and quit screwing around with ******** data. You got to get old school and get the basics right. I'm getting worn out reading that many posts!

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JExpedition07

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I can't believe 45 posts later and you haven't done a fuel pressure test, and checked exaust for back pressure ! Screw a gauge into front o2 sensors and see reading. The reason it ran better with a tune is they fattened up the mixture and advanced the timing curve. I still can't believe you bought it this way, without having them fix it first. What if your motor had been shot, bad valve, rings. Do the 2 things I mentioned and quit screwing around with ******** data. You got to get old school and get the basics right. I'm getting worn out reading that many posts!

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I agree, he hasn’t fixed anything. Maybe it’s running close to how it should stock now but it still ain’t right. A 5.4 isn’t that slow.
 

1955moose

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Imagine how quick it would be if he got the fuel delivery problem right!

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What was I thinking. It will not rev past 3k in neutral, it has a rev limiter.

No, it shouldnt, unless they had one and then did away with it the next year

You got some kinda issue
 
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