Unsteady idle rpm question

[junehhan]

Hey guys, I just had a quick question. When i'm idling sometimes in traffic with my foot on the brake pedal, I noticed that the rpms tend to go up and down just a tad until it evens itself back out again. I'm thinking according to the tachometer, maybe rpm variations of about 50rpms or so until it evens out. Has anyone else noticed this, and is this normal? I don't think i've ever had a car fluctuate it's engine speed just a tad when you are idling in traffic with your foot on the brake pedal.

[SergntMac]

A/C compressor turning on/off?

[junehhan]

I've noticed that it does it whether the climate control is on or off. When I hear the compressor kick on, it will take a slight rpm dive, but will immediately return to normal rpms and won't fluctuate.

[kurly]

In an earlier thread, I mentioned that after I put my K&N Filter and Flowmaster series 40 Deltaflows on, she dropped about 100 RPM to 500-550 with some fluctuation at stop lights, etc. Put her in Park and RPM goes up to ~ 700-750 with less variation. Haven't had her to the dealer yet, but it is on the list.

[junehhan]

Yes, that's exactly what i'm experiencing! It doesn't happen all the time, but when i'm at stop lights, sometimes it fluctuates up and down about 50rpms until it settles down eventually. It seems to do it more when i'm running a lot of electrical stuff in the car and drive aggressively before coming to a stop. I'm at 1800 miles now, so i'll probably have the dealer take a look at it when I take it in for an oil change at between 2500-3000 miles. Probably closer to 2500 miles or even earlier since lately, i've had trouble keeping my foot from flooring the gas pedal :)

[03SILVERSTREAK]

Originally posted by kurly
In an earlier thread, I mentioned that after I put my K&N Filter and Flowmaster series 40 Deltaflows on, she dropped about 100 RPM to 500-550 with some fluctuation at stop lights, etc. Put her in Park and RPM goes up to ~ 700-750 with less variation. Haven't had her to the dealer yet, but it is on the list.

If you go to the dealer, consider returning the factory filter back in the air box. When I went to the dealer for a defective T/C module they opened my airbox and saw the K&N Filter. the T/C module was replaced via through warranty but they also put in the repair report that I was driving with an K&N filter and that was not a good Idea... :nono:

[kurly]

Originally posted by ADELG670
If you go to the dealer, consider returning the factory filter back in the air box. When I went to the dealer for a defective T/C module they opened my airbox and saw the K&N Filter. the T/C module was replaced via through warranty but they also put in the repair report that I was driving with an K&N filter and that was not a good Idea... :nono:

Geez! I trashed the factory filter and put the K&N in along with the decal on the box! What the . . .

[Haggis]

Originally posted by ADELG670
If you go to the dealer, consider returning the factory filter back in the air box. When I went to the dealer for a defective T/C module they opened my airbox and saw the K&N Filter. the T/C module was replaced via through warranty but they also put in the repair report that I was driving with an K&N filter and that was not a good Idea... :nono:

The last I heard is that they can not refuse warranty work due to the fact that you changed airfilters K&N or not. This goes for any make or model of car. Have a K&N in the Firehawke and in the Marauder and the SMs has never said a word about it.

[MarauderMark]

I was told that when u use K&N filters it sucks to much air in which will make the car fluctuates up and down .Thats messed up because i'm sitting here telling ya'll this while lookin at mine brand new in the box. i dont think i am going to install it. It's what i was told so i thought i would pass it on.....

[MarauderMark]

P.S. he said ithe vacume supposed to suck hard and it wont do it with k&n....

[Haggis]

I have K&N air filters in both cars and they both run fine, no problems. Now whether they improve hp or not is a matter open for discusion, I have heard that they offer up to 10% more and that they don't make a lick of difference. I don't know, but if Kenny Brown wants to put one in my car because it is a better filter, I am not going to argue with his experience until someone can prove him undoubtably wrong.

Can't afford the $.02 until I get my allowance.

[kurly]

[QUOTE]Originally posted by Haggis
[B] I don't know, but if Kenny Brown wants to put one in my car because it is a better filter, I am not going to argue with his experience until someone can prove him undoubtably wrong.

Haggis Good Point!

[Mark McQuaide]

Mine does the same thing, unsteady idle, and one time after driving hard on a back road, she died at the next stop sign. Started right back up and hasn't done it since. I complained to the dealer and they updated the EEC, which didn't make a difference to the idle. Since it runs great otherwise, I don't worry about it.

[junehhan]

Well, i'm glad that i'm not the only one, and since my car also runs good, I probably won't worry about it for a while since I don't like the thought of my dealer touching and molesting my baby...............

It happens so little anyway, and really only happens when I come to a stop after accelerating aggressively, which may just be the emmissions gods at work in the ECM trying to minimize emmissions............