AT START with COLD ENGINE THE RPM HITS 1600 with A/C ON and 1400 with A/C OFF. I THINK THAT IS HIGH BY 400 RPM. WHAT IS THE NORMAL
RPM FOR 08's at START with 1500 MILES? THE RPM IS 1000 AFTER A FEW MINUTES of WARM-UP.

 

Sounds about right. Now that the choke is long since gone, the replacement is a feature called "automatic fast idle". Your warm idle should be closer to 800rpm though.

And please, lay off the caps. It's difficult and distracting to read.

 

Agree with Geko -- that's the normal cold start enrichment circuit working. As I recall, it slows down pretty quickly, but it does idle a bit faster than a lot of other cars when it's overnight cold.

 

it is normal for the idle to be above "normal" or above what you experience in the summer. After the engine starts coming up to normal operating temperature the idle should drop. Try starting your car a few minutes early one cold morning. It should idle fast and in 5 minutes or should drop back down.

 

I have the same experience with my 2008 RX 350 with 2000 miles on it. However, I have also noticed that when I start the engine up from overnight parking, it not only idles at higher rpm but also when I lay my hand on the steering during that time, I feel quite noticeable vibration. This vibration goes away after the engine warms up or if I am doing a warm start.

In addition, when I shift the gear to reverse, I feel a big jolt/jerk and the whole vehicle shudders. This jerk is very mild with warm engine.

Are my observations normal?

 

my 350 doesn't go beyond 1200 rpm at cold startups regardless of temp. outside. higher decibels, but no vibrations.

rpm settles down fairly quickly.

 

Now that's what I'm talking about - 1200 RPM would be acceptable, but higher, No! The dealer rep here in Jax, Fl., was trying to "snow" me with "getting to operating temps for tx., etc. The RPM is too high for OAT of 60-80 degrees F. Thanks for the help.
PS. OAT = Outside Air Temperature.

 

It is suppose to be that high. It is designed to warm up to max. efficiency and less emission as fast as it can.

 

My '04 RX330 have the same high cold idle also...usually around 1600 RPM overnight and takes about 3.5 minutes to come down to 1000 RPM. This is really slow compared to my mercedes, which idles at 1300 RPM overnight and drops below 1000 RPM in 30 seconds. My cousin's 3-series is even quicker....idles at 1200 RPM and drops under 1000 RPM in 20 seconds.

 

Normal ops