Hunting idle in the 6 speed

[CoastyAV8R]

I have an 04. 5 with the 600 engine and the 6 speed. When I pull up to a stop sign and push in the clutch to stop, the idle goes down to about 550 rpm then up to 850 rpm and it will fluctuate back n forth about 3 times over the course of 3 seconds before it settles down to idle at about 750. It does it with the A/C on a little more pronouced than with it off but not a huge difference. Has anyone else seen this? The truck has a little over 1000 miles on it and has had no reflashes. I'm thinking a reflash will fix this thing as the truck runs fantastic but I don't know at this point. I like to go in to the dealer with some idea of what has fixed others in the past...



Thanks in advance...

 

[rbattelle]

Does pressing the brake stabilize it?



Mine will tend to hold the RPM at 850 or so if vehicle speed is above 10 with the clutch depressed and just coasting. It drops to 750 when I hit the brakes. I believe this is part of the ECM programming, designed to hold RPM up a little bit in anticipation of a shift or something. Sometimes, mine will oscillate as you described a few times before settling on 850 (until I press the brake). Has done this since new.

 

[Fireman]

Hey buddy, congrats on the new truck. I know you're going to love it.



Fireman

 

[CoastyAV8R]

R-batt, I hadn't noticed if applying the brake has any effect on it or not. I hadn't thought of that one. I'll have to give it a shot and see what takes place. How many miles do you have on yours?



Thanks F-man. I really do love this truck, it hauls butt. You still have the trailer I see. We sold ours when we got here to Texas. I had to live in it for 2 months until we closed on our house, then we sold when we found out to store was gonna run $80 a month. We wound up buying a used a smaller toyhauler that we can store. Hope all is well...

 

[mattymac]

my 600 does the same rpm lug down that yours does but only once to about 550 then up to about 750. Wasnt sure if this had something to do with third inj. event.

 

[rbattelle]

I've got almost 21000 now...

 

[CoastyAV8R]

I did notice that when the brake is applied, the fluctuation seems to pretty much stop. I think you may have something there with ECM's role in this. I'm not gonna worry about this...

 

[EEngel]

Same RPM drop here

My truck is also dropping to 550-600 when it comes to a stop. I guess I'm not real worried about it, but it was a little confusing at first.



I tried keeping the brake on while it was doing it, it still occured.