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Came back from vacation, and started the 01 IS300 and started off to work. Noticed that the acceleration was weak, it has progressively gotten worse. When you first take off, everything is fine. As the engine warms up, acceleration gets very weak. Push down on the gas and the engine sounds like a moped, and takes forever to get to 40 MPH. IS300 has 84K on it. Any advice is appreciated..
 

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Check battery terminal connections (remove, clean, and reconnect). Check for loose vacuum hoses. Did you replace fuel filter per maintenance schedule? Any other maintenance points you may have not done?

Run your diagnostic OBD codes.
 

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sluggish?

This is not a word we use with IS300! I don't know how coincidentally you could have knocked something loose but you might want to check the connection betwen your air intake and your plenum. If loose this can send poor signals to the ecm and make the car run like crap. and sound that way too. The sensors are very sensitive to air leaks
 

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Check battery terminal connections (remove, clean, and reconnect). Check for loose vacuum hoses. Did you replace fuel filter per maintenance schedule? Any other maintenance points you may have not done?

Run your diagnostic OBD codes.
Does the IS need to replace fuel filter ? The service advisor at the Lexus dealer told me the IS uses mesh fuel filter therefore there is not necessary to replace it.
 

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I don't have the IS300 service manual but I have seen for sale (on the Internet) in-tank fuel filters that are integral with the fuel punp. You have to remove the fuel tank -- yikes!

But wait for a more accurate opinion from IS300 owners.
 

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Have your injectors and throttle body cleaned.

Does your RPM's stutter when you at a stop and it feels like its gonna die?
 

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If none of the above help, and you don't have a CEL, have the cats checked. I know first hand what a clogged cat feels like (not on the IS) and it isn't cool.

I am thinking this is what is wrong with my MPG (7MPG loss over the last 6 months). Maybe you have a similar problem?

Is there any sputtering, hesitation, lurching, lag, CEL, etc? Is you air intake tight? Have you visually inspected all the components?
 

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Is the acceleration a slow gradual type or a basic dead peddle till you hit a certain rpm and it lurches forward.

I had a problem with the throttle position sensor where the car idled horribly and was very unresponsive.
I got this issue now whsts the fix if you know it please
 
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