When I stop at a light I feel a very rough idle from the engine for about a second. This has happened a few times already. Everything about the car is fine, but every now and then I feel the engine rumble after I come to a full stop. Is this normal V6 vibrations?

 

Sometimes the RPMs can drop once the radiator fan kicks on.

 

Sounds like it could be the carbon build up issue. Do you have a 250 or 350?

 

It could be that...

I have an is250. only got about 55k miles on the odo. Is there a thread about the carbon build up issues?

 

Yes sir. Two threads, one about the problem and another about how Lexus is trying to fix the issue. Search for carbon build up and both should pop up

 

With the recent heat wave in our area, this same rough idle has occurred a handful of times, under the almost identical conditions as the OP. Prior to this heat wave, it didnt occur. Looks like I will be reviewing the carbon build up thread.

 

I would also add that I started my engine and got going, then lost power while I was driving. Check VSC and engine light came on. Pulled over and restarted the engine and the problem never showed up since then. This happened earlier this year.

 

time to change the spark plugs.

 

Pull out your mas air flow sensor Spray some carb cleaner on to clean it out. Fixed my problem on both my ISF and is350.