My IS350 is intermittently revving on its own at stop lights to like 6k rpm, I have to smash the brake and it still makes the TC come on and does a power brake. It seems to do it when its cold and when its warmed up. I thought maybe it might be the cold air controller but it does it when the engine is warm as well, does anyone have any idea's what would cause this?

 

That is crazy unsafe! If it doesn't have giant vacuum leak and the dash lit up like a Christmas tree you should have it towed to lexus for diagnostics.

You driving it knowing you can't control it makes you liable if anything goes wrong.

That is NOT normal and is very unusual!!!! Please have it looked at before you drive it!

 

I would not even be posting this on a forum. I would have the car towed to the nearest Lexus dealership. Period.

 

Is this a new vehicle to you? Did it start randomly doing this to you out of the blue or perhaps after someone worked on it or repaired something?

CELs?

 

It started out of the blue, Ive had the car since 2016, Im thinking that the throttle position sensor might be starting to go out since its so random. im going to clean the mass air sensor and the throttle body and clean all electrical connections when the weather allows me to.

 

Oh boy, I'd take it in asap to a dealer. That's terribly unsafe! Not worth trying to diagnose it yourself, by trying this or that out. Seriously, I know we'd all like to think we're shadetree mechanics, but there are a lot of electronics on these cars.

 

All of those are great regular maintenance ideas, however what you have now is a 93 Octane powered lawsuit. PLEASE stop driving it and have it looked at by a professional or someone experienced. The tow truck costs less than your insurance deductible. If it happens while driving you dont want to risk other peoples lives.

 

not driving it, have second vehicle, dealer wants $200 just for diagnostic. dont have that kinda cash right now
Also talked to a toyota mechanic at a local toyota shop and he said sounds like a sensor is either dirty or failing, he suggested cleaning everything before i go blow money at the stealership, cleaning the throttle body and all the sensors is pretty basic stuff.