So I understand that Lexus has a idle mechanism that in cold wether the motor will maintain higher RPM's until it warms up...I drive the freeway home here in the frigid upper midwest...as we got colder last year it would take longer and longer for the car to finally lower it's RPMs, which would make sense as the colder it got the longer it takes for the motor to warm up...but here is my issue now this year...my car takes even longer for it to finally shift into the the lower RPMs then it did at the coldest points last season. would there be any reason for this?

I had my car in last summer for a timing belt/water pump and I was told by Lexus that I may have a hole in the manifold (the car idles loud and I get vibrations as i sit at stop lights)...however Lexus said that the fix would be about 450.00 and it's currently not causing any othe issues. Would this be part of the issue? Weight of Oil?

Any help would be great.

 

Was the hole in the manifold, or the Flex pipe onthe exhaust? As for the vibrations it could be a dirty maf sensor, or a worn upper motor mount, the one on the right side of the car. It could just be colder this year.

 

Weld that manifold. Don't get suckered into paying 450 USD for an $80 USD piece of flex pipe. Some things I would leave to Lexus or a good trained mechanic, but there are other things that you can use to save on your budget.

Cooler year, longer time, just as thomas1 mentioned.