P0301,P0303, and P0305 codes detected Lexus -LS 430

Question

All 3 codes are detected at the same time. Could this be because of a timing belt issue or spark plugs?

Answer 1

if you have not replaced spark plugs in 50k miles replace the spark plugs first and check the ignition coil on bank 1, 3, 5

 

timing belt is due 90k miles, or every 7 years if you timing is off that can also cause a misfire.