Roughly 6 months ago I developed this pretty annoying problem that has left my car in a state of unreliability. I was out driving one day in bumper-to-bumper traffic, on a particularly hot day. When I went to accelerate there was no response. All of the dash lights were on but the engine was off. The car keeps leaving me stranded, when it's cold outside it doesn't act up but when it's hot outside it does. I have no check engine light or any stored codes so I am at a loss. I've checked cam and crank signal and everything seems to be all right, I called Lexus to see if all the recalls on this car have been performed I.e e fuel pump pressure sensor. All recalls on this car have been performed up to this point. I was doing spark plugs which as you all know requires you to remove the intake manifold. When I did that I found that the butterfly valve inside the intake manifold looked a little wonky. So I took the motors off and found a nut that had backed itself off of the motor that actuates that butterfly valve. Some loctite and a little effort later that was fixed but the problem still remains. He got home yesterday. She started up again. It was a very hot day and the car wouldn't start. It cranks, revs up dies cranks, revs up dies. When it does stall you were unable to restart the vehicle until it cools down. In the mornings when it's cold it starts up no problem. It's a real head scratcher.

Hello,

That would be a tricky one to resolve over the wire..

At the very least, the first step would be to get a Scan Tool capable of reading Engine Live Data, connect it on a Cold Day and go for a drive until the symptoms start to appear, then look for the Changes in the data, if you can capture either screenshots or the recording of the data, do that and post it here. Not quite sure what to look for specifically in that data as of this moment, but seeing the effects, it is bound to be something quite noticeable.

Hope this helps and best of luck!

Thank you for the reply. I do have a scanner and have driven with it but I can't get it to act up when I have the scanner lol. I have been trying to find cam and crank signal data but I don't believe my autel scanner is capable of displaying that info. It might actually be the Lexus computer that doesn't show that information, not sure. I did notice the other day that when the car had been sitting in the sun, windows up it didn't want to start. I rolled the windows down and came back 5 minutes later and it fired right up. I'm wondering if there is an ignition relay in the car that is getting hot and is partially de soldering but it's hard to say. It's getting frustrating and I don't want to throw parts at it. I'm a little lost at the moment.

How often does the issue occur when the Scan Tool is not connected? My question is, do you think that the car stalls Less with the Scan Tool connected, or you just didn't do enough testing with the Scan Tool Connected for now?

Cam and Crank Sensor Readouts are not something you will find in the OBD2 Scan Tool, for a variety of reasons, not the least of which is the rated Data Transfer Speed of the OBD2 protocol, by the time it would update, you would miss most of the useful information, if you really want to check them, you will need an Oscilloscope. Even then, I can't really see the reason to suspect either of the sensors at the moment, though that said, you can still indirectly watch for presence of Crank Sensor Signal by the Engine RPM readout, the Cam Sensors are not strictly necessary for the Engine Operation.

The simplest test in this case would be to get a Hair Dryer, and with the Engine Started and Scan Tool Connected, go and blast every component required for the Engine Operation with Hot Air, starting with the ECU under the hood, as they can be vulnerable to the Heat Damage, and see if that does anything. Just make sure not to melt anything into a puddle while you are at it..

Hope this helps and best of luck!

Could be your negative battery cable where it connects to your batteries top post isn’t secure. See if you can shift it or rotate it clockwise or counter clockwise with medium pressure using your hand.

Thank you to everyone who is responding and sorry for getting back weeks later. I havent tried the hair drier trick but I will give that a shot. I did notice that when it is hot outside it acts up, case in point it was really hot the other day and the car would turn over and immediately shut off after the gauges did a sweep. I rolled the windows down, came back 5 minutes later and it fired right up.

Have you tried hooking it to Toyota Techstream? Google around how to get it. I think you should be able to get the event history from it, perhaps it will tell you the reason for engine shutting of...