Is it possible to have a malfunctioning coolant temperature sensor (CTS) and still not have a "Check Engine" light come on? This 92 240 sometimes partially floods on startup when hot. About 1/2 of the time it starts within 1-2 revs when hot, the other 1/2 of the time it starts after 5-7 revs then runs on 2 cylinders and takes 10 secs to clear itself, smoking blue or black until clear. Then idle is okay, but not real smooth. This engine never has super smooth idle actually. When outside temp is over 75F, starting acts same way after engine is cooled down. Mileage on this car with auto trans is 22-24 highway. Fuel pressure stays up for 30 minutes after shutdown, so I think fuel pressure regulator (FPR) and line check valve are working okay. What could be wrong here? Injector, if not CTS or FPR? Something else? I holding off on the CTS as it is located in a difficult spot. But I will change it if it's the probably culprit. Thank you for the advice.