Conrad200t

no it’s not normal. If you hear the car cutting boost repeatedly under WOT conditions (full throttle) then you need to replace the VRV (Vacuum Regulating Valve) and possibly the vacuum hose that comes from the waste gate, across the engine, and into the valve body.

If your feeling balsy or are really broke (new valve is about $80-$100 as of late 2023) then the problem is the valve has a small filter inside of the housing of it that just gets really dirty. You could attempt to carefully open it up and clean the filter, then reassemble it and see if that fixes it.

HOWEVER the problem could also be in the valve portion of the assembly (likely an O-ring or gasket/seal) or it could be the motor of the solenoid itself so I think literally everyone and their Lexus savy mother would recommend you just replace the whole thing.

oh and as the problem progressively gets worse you will notice a somewhat of a jerking sensation under WOT, like when u get on the freeway.

ultimately it will cause severe driveability issues, possibly prevent you from even being able to drive the car. But obviously that would be stupid to just not care about it for that long.

hope this helps. Feel free to ask any questions you might have. I’m aiming to learn essentially EVERYTHING there is to learn about this car and all of its systems. Mainly because i really like my car and I pay a god dam fortune (IMO)to have it. AALSO i wanna see how much power/performance i can crank outta this thing before it gives out.

Lex_Giorgio

I just got the F Sport cluster put in and was wondering if this is normal for the boost gauge (all the videos in this thread no longer work, so it's kind of hard to tell what the problem looks like if you're relying on the gauge):

is200t300F

I replaced my solenoid I didn’t have any weird noise but was getting inconsistent boost at WOT, now car runs like new. I looked up the manufacturer and found one that looks like our solenoid but it was for a BMW it was for 90$ idk if it would work but the plug and vacuum hoses go to the same places

carlexu

Hello, I'm from Turkey and there are very few Lexus cars. I have a problem with my 2015 model year Lexus GS200t (at 100.000 km) about turbo boost and performance. It does not related to topic of fluctuation of turbo boost. Fluctuation of boost problem occured 2 years before and I solved by replacing vacuum hoses and VRV. Then, normally, from 2000 rpm up to 4500 rpm, engine were boosting up to 1.1-1.2 bar as in first video. But in one day, suddenly, boost vs engine rpm relation has changed as in second video. It started to boost 0.8 bar between 2000-3000rpm , then drops at around 0.6 bar between 3000-3500 rpm, then from 3500 to 4500 rpm it boosts normally as 1.2 bar. There is no faulty codes or sign. After that problem, I have tried lots of things for several months and spent lots of money. No boost leak could not be found. Vacuum regulator valve, vacuum hoses, turbo turbine (with wastegate valve) part, engine valve cover and pcv valve have been changed with OEM parts but the problem can not be solved. Then, I have tried to remap tuning with ecu flash with a reliable company in my country, Remaps, to increase the boost limit but no changes up to 3500 rpm. After 3500 rpm, boost behaviour is normal without tuning and increased by ecu tuning if you wish.
Also, when I take data on the road test from OBD II, the target boost pressure is compatible with measured boost pressure. That shows the target pressure is also incorrect or different from the one years ago, low up to 3500 rpm. Fuel pressures and other data I take, they seem all normal range. Even if, I bypassed the VRV valve by plugging its inlet and outlet vacuum hoses, that is, stuck the wastegate with full vacuum, then boost increased a bit (only 0.1-0.2 bar) but not as in before.
I need your help, and I am about to go crazy.