My car has less than 600 miles on it and is stock...still breaking it in.

When the car is fully warmed up and i come to a stop (like at a light) and the foot is off the brake and the clutch, the rpm shoots up from 900 to 1500 or 2000 and then gradually goes back down. I have the heater on, but i wouldn't expect the heater to cause this. let me know if anyone else is experiencing this...thanks

 

its normal

 

Not normal..

It may be the floormat hitting the throttle pedal if it is not hooked to the hookie thingie..

Otherwise, could be a Mass Airflow sensor or box issue..
Or something else..

I would just head into and let them take a look if it will duplicate..

 

You probably have the AC or the Defrost on.

 

An idle shooting up??
I disagree..

In the cold the EVO holds a higher idle but I never witnessed it shooting up..ESPECIALLY when fully warmed up..

Are sure nastea??

 

i've seen mine do it...but i have been know to smoke excessive amounts of crack....so don't believe 90% of what i say.?

 

its normal, its the fan of the car cutting off and on....it cuts on more when you have the heater or air on,....try it and youll see your self, our fans turn off and on alot on our cars....no worries dude.

 

with less than 600 miles on it, the ECU may still be learning its idle characterisitcs with different options and the load required to maintain idle under different circumstances.

You can have the dealer check it out, but I'd give it some time.

The safest thing is to at least have the dealer check it out, even if they don't find anything, you have a record that you felt there was something wrong.

For what its worth, the Idle will spike periodically when it drops too low, and attempts to recover, and there are several different reasons for it happening, accesory load, A/C cycling, ECU learning.. If its VERY dramatic and happens very often, then I would become concerned when you get a few more miles on t.

Since the weather is cold (at least here in my area) you might want to allow the car to run for some time with the a/c on so it can cycle at idle a few times over a few drive cycles... that might help things a little.

 

Mine started to doing the same thing after I installed my AMS catback. I figures it was just because the heater was on. When it warms up enough I'll see if it happens without the heater on.

 

Yeah...mine does that, too...no worries...

 

Malibu is correct about the fuel maps and the ecu learning. Normally anytime you disco the battery from the car, the ecu resets . My car is doing this now since I changed out my battery to the buschur battery, about 100 miles ago. It shoots up to 1500 rpm then after a while it will gradually works it way down till you hit around 500 miles after disco of the battery. And if you mod your car and reset the battery it will do it a little longer due to the settings.

 

Yep, I thought that might have something to with it. After putting the catback on I disconnected the battery for about 15 min. Guess the ECU is still learning, altough it didn't do it today.