Sluggishness at 250K — Fluids + Service Plan, any other recs?

[kty]

My 2015 LC200 is just shy of 250k, and I’ve recently noted some sluggishness, especially off the line and when accelerating with moderate throttle. No codes or major symptoms, just feels a bit bogged down.

Worth noting: I’ve got a roof box on top and drawer system in the back, so I’m carrying extra weight — but the change in performance still feels more pronounced than that alone would explain.

I’m taking it in for a 50k fluid service tmrw morning and hoping to freshen things up and gain some more of that oh so smooth V8 power.

Here’s what I’m doing:

• Throttle body + MAF cleaning
• Fuel injector cleaning (on-car pressurized system)
• ECU reset + throttle relearn
• PCV valve service
• (Spark plugs were done at 200K)

Also doing diff, transfer case, brakes, ATF exchange, and power steering fluid while it’s in.

Anything else you’d recommend? Still undecided on a KDSS flush — I’m getting mixed feedback on whether it’s worth doing (Lexus service dept advised against), but that's separate from the sluggishness issue.

Would love to hear if anyone’s chased down similar sluggishness and if you'd add anything to my plan.

Thanks!

 

[kcjaz]

4.88 gears helped my “off the line” performance a lot….

 

[gasman4u]

I've never heard of a "KDSS flush," but since you mentioned a lexus dealer I'm assuming you have an LX. If so, I think the AHC system needs servicing like anything with fluid would. @tbisaacs I think is a good resource for this. I may be misremembering though.

If indeed a LC, my thought would be to leave the KDSS system alone unless you're having issues. There's a lot of people who have had clueless dealers mess up their stuff when they loosen the KDSS screws enough to depressurize the system and lose fluid.

If you haven't already, you're likely due for engine and cabin air filter changes too. I would do the cabin yourself as clueless techs break the recirculation door all the time in their ham-fisted cabin filter changing crusades.

HTH

 

[bloc]

I've never heard of a "KDSS flush," but since you mentioned a lexus dealer I'm assuming you have an LX. If so, I think the AHC system needs servicing like anything with fluid would. @tbisaacs I think is a good resource for this. I may be misremembering though.

If indeed a LC, my thought would be to leave the KDSS system alone unless you're having issues. There's a lot of people who have had clueless dealers mess up their stuff when they loosen the KDSS screws enough to depressurize the system and lose fluid.

This. I wouldn’t let them touch a functioning KDSS system.

If you haven't already, you're likely due for engine and cabin air filter changes too. I would do the cabin yourself as clueless techs break the recirculation door all the time in their ham-fisted cabin filter changing crusades.

HTH

I’d take it a step further and lock the glove box and keep the key blade in a pocket.

 

[kty]

I've never heard of a "KDSS flush," but since you mentioned a lexus dealer I'm assuming you have an LX. If so, I think the AHC system needs servicing like anything with fluid would. @tbisaacs I think is a good resource for this. I may be misremembering though.

If indeed a LC, my thought would be to leave the KDSS system alone unless you're having issues. There's a lot of people who have had clueless dealers mess up their stuff when they loosen the KDSS screws enough to depressurize the system and lose fluid.

If you haven't already, you're likely due for engine and cabin air filter changes too. I would do the cabin yourself as clueless techs break the recirculation door all the time in their ham-fisted cabin filter changing crusades.

HTH

Thanks. If I had an LX I wouldn't have KDSS, only AHC. It's either or.

Engine and cabin filters all done. I use mechanics that know what they're doing, so the cabin filter thing isn't an issue.

 

[TeCKis300]

I would ask them to check out fuel trims and KCLV for indications of contributors if you're really seeing performance impacts other than just maintenance related items. Fuel pump, oxygen sensors, catalytic converters type things.

At that mileage, I'd probably change the oxygen sensors anyways even if they're within operating thresholds, as they're likely degraded.

 

[gasman4u]

Thanks. If I had an LX I wouldn't have KDSS, only AHC. It's either or.

Engine and cabin filters all done. I use mechanics that know what they're doing, so the cabin filter thing isn't an issue.

Right. You're the first I've seen who's had luck in getting your Toyota worked on at a Lexus dealer that I've seen. From what I can glean, Toyota dealerships will work on Lexus, but Lexus won't typically touch Toyotas.

 

[gasman4u]

I would ask them to check out fuel trims and KCLV for indications of contributors if you're really seeing performance impacts other than just maintenance related items. Fuel pump, oxygen sensors, catalytic converters type things.

At that mileage, I'd probably change the oxygen sensors anyways even if they're within operating thresholds, as they're likely degraded.

I asked about the o2 sensors, MAF sensors, air/fuel sensor lifespan in another thread but the OP never got back. How long do these usually last? And do you replace them all at once?

 

[bloc]

I did my A/F ratio sensors at about 195k with no noticeable change in drivability or efficiency. But that's just one data point.

Thanks. If I had an LX I wouldn't have KDSS, only AHC. It's either or.

Engine and cabin filters all done. I use mechanics that know what they're doing, so the cabin filter thing isn't an issue.

Have you found a local shop wiling to do a KDSS flush? Or one that recommends it? The process is involved, and requires tools that are not common.

This board has more american users with our version of KDSS than probably anywhere else online, and this thread is the first I've ever seen it mentioned.

 

[mark71]

The KDSS should be flushed after long snipe hunts.

 

[bj70bc]

maf, plugs, O2, unplug the battery for a couple hours, will probably take care of it

 

[TeCKis300]

I asked about the o2 sensors, MAF sensors, air/fuel sensor lifespan in another thread but the OP never got back. How long do these usually last? And do you replace them all at once?

There's no maintenance or replacement intervals on these and they can last for the life of most cars depending on use. As you mentioned noticeable performance decrease is why it's worth looking into them. The ECU will compensate for most degradation of MAF, injectors, and even the fuel pump, but it is the O2 sensor in particular that provides feedback for compensation. Over its useful life, it'll lose accuracy and response speed. At 250k miles, it's worth changing IMO. I'm nearing 200k and will proactively change mine at that point.

Still, I wouldn't just throw parts at it either. Check the fuel trims to see if the ECU is compensating for something. You may have something as simple as a vacuum leak with worn hoses.

 

[bj70bc]

maf gets real dirty over that many miles, could be past the point of compensating, plugs arent lifetime like they say, just that could do it, ive seen them worn right off before, O2 could do it but they usually throw a code, i used to find my tundra would get lazy if you always drive it like that, perhaps trans learning bad habits is contributing

could have a stuck caliper too, youre in the window for them to start to go bad

 

[grinchy]

If you really want it all back, you need new ignition coils and a/f and o2 sensors.
Rock auto for known non counterfeit coils, denso is the OEM supplier.
They’re also a fine option for the sensors.

 

[kty]

I did my A/F ratio sensors at about 195k with no noticeable change in drivability or efficiency. But that's just one data point.



Have you found a local shop wiling to do a KDSS flush? Or one that recommends it? The process is involved, and requires tools that are not common.

This board has more american users with our version of KDSS than probably anywhere else online, and this thread is the first I've ever seen it mentioned.

FWIW, my shop and the Lexus dealership I called both said don't do it, no reason to. It's also pricey so I'm happy to skip it. FWIW.

 

[kty]

Right. You're the first I've seen who's had luck in getting your Toyota worked on at a Lexus dealer that I've seen. From what I can glean, Toyota dealerships will work on Lexus, but Lexus won't typically touch Toyotas.

I called one Lexus dealer in Austin, and they wouldn't. Called another 15 miles west, and they said of course. So go figure.