Have a '93 LS400 with 138K miles. Had a complete tune-up w. new wires, plugs, coils, etc. one year ago. A few days ago my mechanic put in a new. starter motor and replaced the valve on the side of the power steering pump. Car began mis-firing and the mechanic showed me that some of the wires were arcing, causing the mis-firiing. He changed the plugs and we just put in new wires (inexpensive ones from Advance Auto). Within minutes one of the wires began arcing again and the engine started mis-firing. He said it was because the insulation is too thin, and the wire touched a hot hose which caused a "weak spot". He adjusted them, and for the moment the motor runs smoothly, but we are going to replace the wires with better insulated ones.

Does anyone think there could be another problem causing this situation, like coils producing too much voltage? I am not anythink like a "wrench".

Thanks.

 

stupid mechanic, replace with one that functions correctly and doesnt blame "hot hoses" for melting spark plug cables.

consider that most hoses would melt before melting the insulation on a cable....

 

^^what he said.

whats why the covers are there, for that purpose. if properly put together then u should have no problems with a melting wire.

 

maybe he looped it wrong and the timing belt caught and ripped one when it spun around...........

 

good observation willhickey - also the valve/wire covers can "pinch" the wires if they are not placed properly in the clip channels and cause the same effect.

mine are stock thin insulated wires and never had an issue with them - I would also search for a mechanic that is better suited to Lexus vehicles. this moron may be playing you and have you dish out more cash for something that does not need to be repaired.

be careful