1993 LS 400 85,000 mi. At cold start engine races to what sounds like full throttle for about 10 seconds. Extremly loud roar, then it quiets down to what seems like a normal cold idle speed. We do not touch the acclerator pedal, just turn the key to start.

Is this 10 second high RPM very loud roar normal ? Thanks for any comments. - Herm

 

How did your car behave before? I don't know about the "loud roar", but RPM always higher when you start your car in morning, that is perfectly normal for every car. Maybe you have an exhaust leak somewhere that is why you hear a "loud roar"?

 

Just acquired the car so I don't know if this is new. It is not an exhaust leak, as I said, it is racing to near full throttle RPM's for about 10 seconds on cold start. Much faster/louder than cold start on other cars I have owned. Any first gen LS owners out there who could describe how high their vehicle revs on cold start and for how long ? Thanks - Herm

 

Not normal. Time for a visit to the service dept.

 

mooretorque - thanks for the fedback- can you expand on "not normal" ? Does anyone know the cold start sequence, correct RPM, etc. ?

As far as the advice for a service dept visit is concerned, that is a last resort for me, I prefer to do all my own work, so far have done pretty well . Lexus is new to me though so I am looking for info and learning. Thanks - Herm

 

my cold start rpm is around 1500 to 2000 rpm, but never higher, that is what I call normal hee hee

 

Herm, you mean full throttle, like 2000-5000 rpm for 10 seconds? Please give us more details or numbers. It could be the Idle air control valve( very rare), throttle plate sticking or you may heard the noise from the power steering pump that low on fluid?