2WD Expy 4.6-Slow Acceleration

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BattleRat

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2WD Expy 4.6-Trans Issue?

Hey guys! :favorites37:
I am pretty new to these forums so sorry if I posted this in the wrong section.

I have a 99 Expedition XLT 2WD 4.6 V8 Triton with about 192,000 miles.
At about 154,700 I had the engine replaced with a refurbished one due to issues with the timing chain. After that everything was working great. A little while after I started having rough idle issues, so I replaced all the EGR system components and cleaned the intake manifold. Then again after that, everything was running smooth.

Now, just recently I started having issues with sluggish acceleration while getting on the highway. While I am on side streets everything is fine, gears switch, and everything is great. Once I get on the highway and push the pedal down, it is really slow to accelerate. The same thing happens when I try passing someone on the highway... it is just a pain trying to do that. There is also NO CHECK ENGINE LIGHT.

I am having trouble figuring out what it might be. I had the exhaust system checked for holes and that is all good. The O2 sensors are also working fine. The oil is changed regularly as it should be. Air filter is also new. I even replaced the fuel filter, and cleaned the fuel injectors.

My mechanic (the one that replaced the engine for me) told me that it could possibly be an issue with the transmission. That made sense to me because we replaced the engine but left the old transmission which is basically an accident waiting to happen.

Any ideas on what it could be, or is there anyone out there that is having the same issues?

Thanks for your time, and sorry for the long post! If there is any additional info you need, feel free to ask.
 
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BattleRat

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*UPDATE*

I was just reading some forum posts about overdrive... and what exactly it is that it does(sorry I am a noob with that stuff). Well I thought I should mention that I have been driving it with OD off since the refurb engine was put in. Every time I turn the car on to drive, it starts off, and I never turned it on since then.

Could that be a reason for the slow accelaration when I get on the highway?

Thanks!
 
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BattleRat

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Could this have anything to do with the spark plugs? I don't think they have been replaced in over 32,000 miles. I was thinking that could be the issue, but then it would give a CEL... which I am not getting.

Any thoughts?
 

JUST4FUN

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When you turn the key to on (but not start) is the engine lite coming on ?
 
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BattleRat

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Yea it's on. I checked for codes even without it and no codes. Its weird. Ive been doing some research and I think it could be a clogged CAT. I will check the O2 sensors with my scanner to see.


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BattleRat

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Alright so more had happened!

I checked the o2 sensors and bank 2 sensor 2 was stuck at a constant 0.04 volts... Taking the initiative I thought that meant a bad sensor so I went and picked up a new one, put it and and hooked up the scanner. Now it was changing to numbers between 0 and 0.04 ... Keep in mind I didnt drive the car after replacing it, but I drove it right before replacing it...

My questions are... Is it supposed to be at a constant voltage like that, and do i need to drive the car a bit to start getting the correct reading on the new sensor?

Thanks again!

PS: I added a pic to show you what was happening!


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7a6y5etu.jpg
 
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JUST4FUN

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Im pretty sure that the o2s are disregarded till the truck goes into closed loop so yes driving the truck is a must plus I saw a p1000 code this means the truck need more driving till all the monitors are set bank 2 sensor 2 is a monitor
 
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BattleRat

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Yea Ive been driving it a bit, and it seems like it has gotten better.

I just don't understand how the second sensor has much to do with performance? I mean I know it makes a difference, but I didn't know it was that much.


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