20 Most Recent 2000 Lexus LS 400 - Page 7 Questions & Answers

Okay, I am not convinced it is the spark. But there is a chance. The fact that torching the plugs allowed it to start tells me you engine is flooding. Do you smell gas? If you open the throttle body with the air cleaner off, does vapor come out when the engine had recently cranked? If it is electrical, then power to both ignition modules is failing, which means A. the ECM is not providing power to the modules, or B. The engine crank sensor has failed. The Cause could be a bad connection to the ECM.A scope will indicate whether or not the proper pulses are being input and output from the ECM to the modules. Of course it will need to be tested when it is not working compared to when it is. When cranking, the tach should move indicating rotation of the crank, if not, there is a good chance the crank sensor is no good.

Have the cold start fuel inkector checked for flow.

I'd have to guess that one of the door switches has failed. Check one by one and replace the bad one.

Need to know what year and what engine size you have in order to help....

Check the fuel filter and the fuel pump. Also check fuses.

Which fuse??

Look wireing harness that is close to it and strip the tubeing from or tape and see for a broken wire

it's an extremely hard thing to do without a diagnostic computer, because you need to see its reading compared to other variables while the engine is running.

battery and connection,spark plugs,fuel filter,air filter,starter.