Hey Scotty, 

I wanted to preface this by saying thank you for all the information you provide for the car community. 

My question is: would you happen to know anything about why my 1994 Lexus SC400 (127,XXX miles, automatic) is failing to stay on?

The battery and starter look to be working well, but the car will not stay on unless I maintain my foot on the gas pedal. I have had to two-pedal (brake and gas) drive my car 3 times to the shop now. The shop claims that it is the idle-air control valve and has claimed to rebuild it twice now, but to no avail. The last time, it worked for a week and now the same issue has resurfaced again. I'm racking my brain trying to figure this out and this has left me very sad as I have known this car to be supremely reliable otherwise. 

Thanks for any help you can offer me; if I didn't live in California I would have loved to drive this to you so you could look at it in person. Please let me know if any pictures/anything else would help. 

Cheers and thanks for any help! 🙂