My 2000 maxima rev's a little on a cold start.

[Tom Dubya]

Hey guys new to the forums and was wondering if you guys had any ideas. I bought this car a few months ago with just under 70,000 miles on it for $5700. A few weeks ago i started noticing that the rpm's rev every so slightly in idle when i start it cold. It kind of sounds like "RrRrRr". THe rpm's start out at around 1500rpm and after about 1 min. of idle it goes just under a 1000 like it should,but thats when the fluctuations in rpm's start happening. After a few more min. when the engine warms a little it idles fine. Any Idea's?

[DevonD]

Well when your engine is cold the car will rev up on its own just to help the engine warm up faster. Once it has got some heat in it your engine will come back down to idle. on a cold day this will probably take a good five minutes though.

And do you have auto climate control? If you do then your rpms will move around a bit when your a/c compressor turns on and off. It doesn't sound to me like anything is wrong. just your car warming up.

[Sentientbydesign]

Welcome to NICO.

Like DevonD said, your engine normally will adjust to a higher idle on cold starts.

What concerns me is your idle though. You said it normally idles at 1k rpms? IIRC, your Max should idle at around 650-700. 1k at normal operating temps is a little high.

[Tom Dubya]

Thanks for your replies guys. I think maybe I miscommunication what my concern is. Its not that it goes from 1500 to just under 1000(maybe 800 or 900, i'm not really sure). Its that when it does hit the normal warmed up idle for a minute or so the idle revs up and down every so slightly. Like "RrRrRr". It probably fluctuates within a 100 rpms so you can barely see it on the rpm gauge but i can hear it and feel it. Sorry if i'm confusing you guys, i'm tryin to explain it the best way i can. None of my other cars have ever done it. Thanks for any input.

[DevonD]

after driving to work or somewhere what is it's idle? 650-700? Just letting it warm up for five mins in the drive way isnt going to get it up to full operating temp.

and once it has warmed up where is it jumping around from? like 600- 1000? or what?

[Tom Dubya]

After it fully warms up it drives fine and idles properly. Its just for that minute or so when it comes down from that initail 1500 rpm's on the cold start that it does that RrRrRr thing. And its very minor in how it fluctuates the rpm's, you can just barely see the rpm needle going up and down. But it is pretty rapid. I'm not to concerned with it right now i just want to avoid any future problems if there might be any. I'm not sure what the idle rev's at exactly when it is fully warmed, i'll have to go check it when my wife gets home with the car.But just let me say again that this only happens when the car is just warming up,after that it idles good.

[DevonD]

Would it be possible for you to take a video? Depending on how cold it is when i start my car it had different idle speeds. if its really cold maybe 1500 rpm and if its just a little cold maybe only 1000 or 1200. As your car warms up the idle will slowly come down. its not going to just jump from 1500 then be all done warming up and go to 700.

But a video would help out alot! the "RrRrRr" noise? does it sound like anything out of the ordinary? like a grinding or something?