No Power Until 3.5k RPM, then puts you back into your seat. Also has Ticking/Tapping/Knocking Noise

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RoryTheFerret

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2005 Expedition 5.4l with 140k.

SYMPTOMS:
- For several months we've noticed that the power was slowly starting to diminish, however 4 weeks ago while towing a trailer we really noticed that the power was gone, fuel economy is very bad now. It has so little power it cannot overcome the rear brakes to burn out (we don't do this on a normal basis) fuel economy has dropped significantly.

the vehicle seems to have its power in the morning when we first get going (maybe a minute) then the power is again gone. It also got its power back for 3-5 days 2 weeks ago then suddenly it went back to the way it is.

Power Loss - The car lacks power in all gears and RPMs until it reaches 3500rpm then it kicks you back in your seat while under acceleration. It feels like the brakes are on until that RPM.

Clunking Noise - At around the same time the car also started making a tick, click or knock "clunking tick" that is coming from under the car (louder from the passenger side door), testing with a stethoscope revealed it loudest from the torque converter area. The clicking increases and decreases with engine RPM.

No Codes or CEL are detected

REPAIRS & TESTS:

COPS & Plugs replaced by previous owner -2016

Transmission & Torque Converter Repaired by previous owner -2016

Cam Phaser (Dorman) replacement in 2016 new timing gear & oil pump (Cloyes) $1000

Fuel Filter 2016 $20

New injector Cyl 5 2017 $50

Catalytic Converter Tested (compression tester inserted into O2 sensor bungs, 0 PSI reported)

COPS, MAF, TPS, Fuel Rail Sensor swapped from working 5.4l

VCT Solenoids replaced $40

SeaFoam'd Intake, Marvel'd Oil & Fuel

Disconnected each COP to see if noise went away, nope

Changed from 5w20 to 10w30, nada.

Checked plugs for damage and being loose

EVIDENCE:

A problem in the engine (or drivetrain) is preventing the vehicle from accelerating properly until 3.5k rpm that is undetectable by the computer and only occurs when the engine is cold and not running for several hours.

HYPOTHESIS:
A Cold Engine Provides The Right Conditions -
The truck has much more power when cold, it's possible that the conditions are right when it's cold for it to function properly. Possibilities such as more fuel when cold, O2 sensor taking time to warm up, engine oil being thicker, transmission fluid being thicker, but what could cause it to lose power?

Torque Converter - Though the noise is coming from the torque converter area, I fail to see the connection between it and the RPM. Searching issues with torque converters hasn't revealed that it's possible for the torque converter to cause this kind of issue (it's not torque converter slip).

Phasers - Would phasers cause the vehicle to lose so much power? The phasers were changed just 1 year ago. I estimate it has less than 50% of its power.

Lifters - I've heard of lifters getting stuck on these engines, however is it possible for it to suddenly unstick at 3500 rpm and stick again at lower rpms?

Vacuum Leak - we did some tests for vacuum leaks with starting fluid but didn't notice a change (I'm pretty bad at diagnosing vacuum leaks) perhaps there's a better test?

Transmission Valve Body - Perhaps there is some debris in the valve body that takes several seconds to clog a passage and somehow has the effect of having the brakes on until 3.5k rpm. I also don't see the connection of this to the 3.5k rpm of the engine.

Clogged Cat - Though the compression tester gauge read nothing, a clogged cat would definitely reduce power. Is it possible for it to suddenly open up after 3500 RPM? Is it possible for it to accelerate fine when first started cold?
 

Habbibie

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U know I was feeling the same in my 05, similar mileage to you, changed the all the cats and 02 sensors at the same time.... now it screeches tires if I give it more than half throttle on take off, I'd be at a 100mph on the on ramp before I merge before that is be lucky to see 65
 

jeff kushner

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Rory, are you sure that your tranny isn't slipping? Is the engine rev'ing but not producing power or is it not really reving until 3500rpm when all hell breaks loose?

jeff
 

Habbibie

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Rory, are you sure that your tranny isn't slipping? Is the engine rev'ing but not producing power or is it not really reving until 3500rpm when all hell breaks loose?

jeff

I highly highly doubt it's transmission related, if your trans won't let you out of first until 3500 then you would know, doesn't matter how uneducated in the works of automotive mechanics you are, the epic clunk that'll occur will be to too serious not to mention here at the title of the thread.
 

jeff kushner

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Dunno...the O P said the noise came from the TC didn't he? Just trying to eliminate slippage....of course we could let him answer....


jeff
 

Habbibie

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Rorythefarret is only here to help himself and nobody else, just look at his previous posts. I highly doubt he'll chime in anyways unless he as another question.
 
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