RX400H 2006 - Code P0300 - Missfire - Flashing engine light

[Richard 86]

Cruzing down the motorway yesterday, and the orange engine management light started flashing.

My general rule of thumb is if it's red, pull over, orange, take it easy and just get home.

It flashed for about 60 seconds, then turned off for a bout 5 minutes, then flashed again for about 60 seconds then never came back on again.

Car drove fine with no other symptoms.

Read the codes and had seven codes.

• P0300 (multiple missfire)
• and then a code for a missfire on each cylinder.

Apparently, if it flashes, then it's serious and you should pull over. Oops.

Something about preventing excess fuel knackering the cat.

So what are the suggestions from here? I was going to check for vacuum leaks. Figured it can't be plugs, as it probably wouldn't be all six.

How does the car know there was a missfire in all six cylinders?

Also, how does it know that the cat is at risk of overheating overheating?

Understanding what data the ECU uses to trigger faults gives me a little more information.

Since the car drove fine, I tempted to believe it's a false error, but unsure at this point.

[katabrontes]

Rather like what happened to me in France a few years ago.  After a few failed attempts it was tracked down to one faulty coil on a plug by Lexus Bordeaux.

I was rather surprised that their diagnostic system couldn't pinpoint the fault to the actual faulty component.

[Richard 86]

Do you remember if that one faulty coil gave you codes for multiple cylinders or not?

Wonder how they established which coil it was. I guess you could use trial and error if it consistently throws an error.

[katabrontes]

Not sure as I couldn't read the codes. It was all done by Lexus agent in Bordeaux.