Just got back from the dealer. Diagnosis: Brake booster malfunction. When foot goes off the pedal, the actuator is taking a long time to disengage. This does not allow the gas pedal to work, because the computer is confused into thinking the driver has one foot on the brake and the other foot on the gas simultaneously. The brake pedal always wins that contest.
Note: I only drive with one foot, with the exception cars with manual transmission! I learned to drive in a Volkswagon Squareback.
The dealer quoted close to $4,000 to do the entire repair. The quote did not break out labor from parts, but when I checked with my go-to mechanic, he said they would charge about $400 labor to put "it" in, whatever "it' happens to be. The part itself must be exorbitantly expensive?
That's when things got interesting: My local mechanic tried to look up "brake booster" as a stand-alone part and could not find it. The current thinking is that (perhaps) this is an assembly that includes the brake booster? I need to research this more.
I did find some possibilities on ebay, including these:
https://www.ebay.com/itm/01-05-OEM-ABS-Module-Brake-Hydro-Booster-Master-Cylinder-Pump-Lexus-GS300-GS430/402599096559?fits=Year%3A2001%7CModel%3AGS300%7CMake%3ALexus&hash=item5dbcc6b0ef:g:XGoAAOSwlXJf0hit
https://www.ebay.com/itm/98-05-LEXUS-GS300-GS400-GS430-AISIN-ABS-BRAKE-BOOSTER-MASTER-CYLINDER-OEM-X5318/254860792391?fits=Year%3A2001%7CModel%3AGS300%7CMake%3ALexus&hash=item3b56e31247:g:O0kAAOSwqBZgIYY8
https://www.ebay.com/itm/98-05-LEXUS-GS300-GS400-GS430-AISIN-ABS-BRAKE-BOOSTER-MASTER-CYLINDER-OEM-X5130/254873710361?fits=Year%3A2001%7CModel%3AGS300%7CMake%3ALexus&hash=item3b57a82f19:g:zxoAAOSwfwlgEbiC
Not sure how to identify and find this mystery part. Can anyone provide any suggestions?
Perhaps if you order it OEM is comes as an assembly and that's what makes it expensive?
Or perhaps if you can get the part by some other fashion, the assembly can be upgraded?
That's what I've got right now... Thanks for any tips.
P.S.: The Lexus guy did suggest (if possible when driving) to take a few seconds between releasing the brake and pushing the accelerator. I tried, and it did seem to help, but not completely all the time.