bluegs

My 2000 GS400 had CEL and VSC warning lights with code 1128 and a rough idle. I cleaned the MAF sensor but it made no difference. After I took the engine cover off, I found a broken vacuum hose, which I repaired. When I started the car, the RPMs were high, so I turned off the key and started up again. This time, everything was normal and it's been fine ever since. The car has 177,500 miles but the engine runs like new again - smooth, quiet and powerful. This is another example of just how ambiguous and misleading the diagnostic codes can be, usually with costly consequences to the owner. My car has not been at a dealer since 60,000 miles and it's running great. I recently had the timing belt/tensioner/idler pulley/watt pump pump replaced (first time, not by the dealer) which also made a difference.

My 2000 GS at 175000 is still fast, but my wife's RX300 became very sluggish a month ago. It was the MAS airflow sensor - it just needed cleaning and the car has been much more energetic ever since. Could there be a sensor problem that's causing the ECU to detune the engine?? The RX did show a trouble code, but it was quite ambiguous.

My 2000 GS400 has 175000 miles but you'd never know when you step on the gas. I finally had the timing belt and water pump replaced for the first time last week - the engine is much quieter now.

I found my GS400 still had some front end looseness after installing the L-tuned struts and springs with 18" rims. I added the TRD strut tower bar and this made the front end handling tight and predictable. I've seen other postings where the strut tower bar was claimed to be more effective in this regard than the lower chassis brace. This makes sense because the chassis brace cannot stop the strut towers from flexing and changing the steering geometry during hard cornering or over bumps. Of course, you could put both on the car...

There is probably no way to adjust the idle speed on this car. Typically the idle speed is controlled by the ECU based on sensor inputs. I'm not surprised you couldn't find an idle adjustment screw, I doubt there is one.