I have this Lexus Rx350 2009 model, it works well, moves fine but after driving for about 10 minute goes into misfire mode, hesitating and stumbling and check engine light comes on, if I park and restart the engine everything goes back to normal, a scanner pulls the code p0300 random and multiple misfire. Gurus what should be done to fix this. Thanks

leadknight123:
I have this Lexus Rx350 2009 model, it works well, moves fine but after driving for about 10 minute goes into misfire mode, hesitating and stumbling and check engine light comes on, if I park and restart the engine everything goes back to normal, a scanner pulls the code p0300 random and multiple misfire. Gurus what should be done to fix this. Thanks

This is a random cylinder misfire. Check the following

1)Fuel pump pressure using a fuel pump pressure tester
2) check condition of sparkplugs
3) check air filter
4) check throttle body
5) check condition of injectors using a ultransonic injector testing machine which can clean up injectors as well and check spray pattern
6) check your ignition coils as well

I hope this helps

So far all this has been done except for change of ignition coils but I think the bad coil should show using a scanner but it's random, plus why does it go back to normal when I off the vehicle and restart it. Thanks Mayor2013

leadknight123:
So far all this has been done except for change of ignition coils but I think the bad coil should show using a scanner but it's random, plus why does it go back to normal when I off the vehicle and restart it. Thanks Mayor2013

The same thing happened to my 2007 Lexus rx350 and I changed the fuel pump and that was the end, pls replace the fuel pump.

leadknight123:
So far all this has been done except for change of ignition coils but I think the bad coil should show using a scanner but it's random, plus why does it go back to normal when I off the vehicle and restart it. Thanks Mayor2013

If all this has been done and you still have a misfire. Job isn't yet completed. Car needs a proper diagnosis.

leadknight123:
So far all this has been done except for change of ignition coils but I think the bad coil should show using a scanner but it's random, plus why does it go back to normal when I off the vehicle and restart it. Thanks Mayor2013

It goes back to normal simply because, restarting the vehicle resets the computer....
After you restart the vehicle, it scans again and splutters.