My 05 Limited, 6-speed, started to exhibit an odd idling behavior a week ago. When the clutch was depressed with the car car moving, the idle would go to 1500 and stay there. Once the wheels came to a complete stop, the idle would drop to normal.

As I am approaching the end of my 7-70 coverage, I thought I would have the dealership look at it. The car was throwing no codes and the signals at the TPS were on spec, but the MAF appeared dirty, so the tech cleaned it and pronounced it fixed (to the tune of $100 for diagnosis.) And it worked great. For two hours.

Now with the car moving and the clutch depressed the idle fluctuates between 1000 and 2000 RPM until the wheels come to a stop. At that point the idle returns to normal.

Today while cruising at 45 I hit the clutch to shift and the BAS/EPS light came on steadily. At that point the engine dropped to normal idle and the pedal had no impact on engine speed. I coasted to the side of the road and shut the ignition off. When I restarted, the EPS light went off and throttle action returned. However it still does the wild idle fluctuation with the clutch pushed down and the car moving.

Car has 67000 miles and it has the original battery if that means anything. Car has given me zero problems since new.

Any ideas?

 

I think the standard answer from most would be to get a new battery and report back.
That battery has been a good and loyal friend, send it to the recyclers.

 

Yea, I have the idea your battery is seven years old. I have NEVER expected a battery to go past three years (I am from Michigan and they just don't last very well in the cold) it just amazes me how many people will just let a battery go as if it will last forever.

If you hang around here any amount of time, you will find that old batteries will START the car fine, but, oddly enough, they seem to cause various other problems.

YEARS ago, the electrics of a car were simple, and a battery did almost nothing but turn the engine over to start it.

TODAY, the complicated electronics need a CLEAN source of power. The alternator produces a ripply output that is filtered ONLY by the battery. Old batteries don't filter well.

 

OK. Did the new battery thing. (NAPA #7548, $114 + tax) Sorry to say the throttle problems remain, although I'm back to original issue: 1500 RPM idle until the wheels come to a complete stop. Then it's normal. At least I haven't had the EPS light issue again.

By the way, the throttle system is not covered by the powertrain warranty. It only covers "things that touch oil" plus the water pump according to the dealership service man. So I'm going to live with the high idle while the car is moving and wait for further developments.

 

Depressing the clutch operates a switch that switches off the cruise control momentarily, I wonder if this has anything to do with the problem, even if the cruise is not on.

 

Not up on the N/A models, that much. I would, just for the hell of it, do a throttle reset. Throttle position sensor, TPS, can do strange things from time to time. But, usually a high idle would be associated with the MAF sensor I would think on the N/A version. Just remove the engine cover, and make sure all the hoses are in place. This can cause a high idle if one of the vacuum hoses are off as well. Just some things to look at or try. There are some threads on here about the MAF sensor, throttle reset, and vacuum leaks. Good luck.

 

Another possibility is the APPS (throttle pedal) as it has a rheostat in it similar to the throttle body. When it went into limp mode, it should have thrown a code. Power off and restart tells me something is being reset. Possibly throttle body TPS or the APPS.

 

Last two suggestion are things I thought about. Vacum check first. Try throttle reset also but even if reset works likely the symptoms will return if you don't fix the issue.

 

180, this is a very interesting post, and good to know.

I rarely ever use Crusie, I just don't trust that set-up in any car.

Although I would have thought that depressing the Clutch would just shut it off, rather than a momentary action.

If I designed it, the brake, gas pedal, or clutch, would cause the CC to deactivate.

Any ideas on the reasoning behind this.

It's a strange bird that depresses the clutch, not change gears, without playing with the gas pedal a little. Unless maybe your going to neutral with a brake to slow or stop coming to mind...

 

Can't really say about the clutch switch and the CC, but I can say that hitting the brake on my automatic DOES completely reset/disable the cruise. BTW: this is the BEST cruise control I have ever had on any car I have owned.

 

I use the cruise on this when ever I can and I have to agree, the cruise control on this vehicle is one of the best I've ever used if not the best. Maintains speed accuracy on it's own very well, adusts on hills very well and I like the stalk funtionality better then most other vehicle controllers.

 

Did the throttle reset and all was well for 10 minutes or so, then back to malfunctioning. I'd feel better if it would throw a code or something. Now it's developed an occasional habit of feeling like it's stalling at a complete stop and then it blips itself to 2000 RPM followed by a nice steady idle.

Wonder if a Mercedes tech could diagnose this with more certainty than the Crossfire tech at the Chrysler dealer...

 

i am having the same issue, only mine started happening after i installed a needswings intake. it doesnt sound like it has happened to you, but mine check engine came on about the same time this started occurring. the code was for rich/lean mixtures, which would make me think it has something to do with the MAF being confused, however visually it appears to be fine and i am not willing to spend the money to buy a new one and find out. best of luck

 

I wanted to bring this thread to your attention as it appears all of us are having similar issues. I thought at first it may have something to do with my new 74mm TB, but at this point we have ruled that out, but stilll have no idea what it could be.

Member Max Cichon has just jad his towed to the dealership after it stalled on him, so hopefully we will know something soon, but just thought you may want to take a look...

https://www.crossfireforum.org/forum...ging-idle.html

John

 

Was the problem ever solved? I'm having the same issue where I push in the clutch and the RPM fluctuates between 1k and 2k until I come to a complete stop. I'm tired both of this happening and mechanics saying they've fixed it when they haven't.

 

It occurs to me that, when the wheels are turning, it would seem that the ECM is keeping the engine revved up in order to provide for a smoother clutch engagement. I've had two manual Crossfires and I believe they both did this unless you do a throttle reset -and as soon as the system re-learns, it goes back to doing it.

What I am saying is that I believe this is normal. The ECM KNOWS the wheels are turning, it even knows how fast they are turning, the brake controller/antilock computer tells it what is going on. Remember, the stability control system has command of the throttle.

I really think this is normal. My Ford Ranger even idles high with the clutch in when moving.

Note that, when I posted here years ago, all I responded with, was "Your battery is too old". If you read my post, I said nothing about his actual complaint, mostly because I don't think his complaint is valid.

 

I would agree with you on saying that it's supposed to do that if it did this every time I put in the clutch but it is very unpredictable and erractic. The only way to ensure that the throttle doesn't fluctuate is to put the clutch in when the RPM is under 1k.

 

Ok, so what other symptoms are there? What else is the car doing that seems out of line?

And if it EVER warms up, I'm going to get mine out and see how it acts when I push the clutch in at, say, 45mph. It's just not something one does, who knows how it acts when you do that?

 

If I put the clutch in while the RPM is over 1000, the RPM will rev up to 2500 then drop down to just over 1000 and repeat, until I come to a complete stop. It's been doing this at increasing frequency and now it does it almost every time.