Hi. The last time I was out the management light came on and when I got home I got code 172&175 which is both banks running rich. So I pulled a plug out and expected it to be black and it was normal tan colour. So I cleaned the air filter and air flow sensor. Now she's idling @1500 rpm and can't get it down. So wondering if the pressure regulator is sticking. Which used to be easier to find on less complicated engines lol. The lexus has so many valves and solaniods on the engine lol