thatstang

It seems to be more pronounce in the morning but my car seems to idle kind of high when I slow down. When I pull up to a stop, my idle shuts up to 2500 and then down to 1500 and back up to 2500. It does it several times before droping to preset 725. Becoming annoying since it will do it if I cruise very slow in Netrual in traffic. Sounds like I am reving engine on purpose but my foot is off the gas.
Any suggestions? It is fine once I come to complete stop and let it finish its cycle but very annoying if have to go through traffic.
Before I take it to dealer I guess I need to pull my CAI and return to stock :-(

tmritter

Thatstang:


I have the same issue with mine (a manual V-6). It drives me CRAZY. When I put into neutral and drift up to a stop sign, even if I am barely crawling, it can shoot up to over 2000 rpms. If I push in the clutch (and hold it in while coasting) it does not do it. And...it does not do it all the time, only sometimes!

I have seen this mentioned on other forums, but no solutions. If the dealer is able to correct this problem, please let us know!

DragonPL

Its to do with emissions and the O2 sensor. All manual mustangs are like that…Talked with a guy with a 2002 Saleen and it does that too, and other manual Mustangs I drove do the same thing, I had to change the way I drive, meaning less crusing in Neutral, or floring the cluth when doing so....

thatstang

As long as it doesn't damage the engine I am ok, just annoyed :-)
One way to temporarly relieve that after tune is to do the acceleration depress trick while engine is off to reprogram fly by wire but it works only occasionally. Oh well, such as life.

flapjack

@thatstang

What trick is that. It's the first I've heard about it. I have noticed after a tune it doesn't happen quite as much, but it's not worth retuning every few days.

It does **** me off, though....

Pony Tail

Mine does exactly the same thing ('06, 4.0V6, 5spd manual) Drifting along in neutural in slow traffic, revs to 1500 -2000+ rpm. Drives me nuts too. I'd love to hear the definitive word on this issue.

thatstang

trick is to turn on egnition.
Press accelerator all the way to the floor and release.
Turn off ignition for 5-10 sec and restart car.
Worked great to decrease lag time before programming and might work for this idle issue.

With my muffler it sounds like I am reving my engine in traffic and get strange looks from folks ;-)

flapjack

Thanks, I'll try that and see if it helps.

thatstang

still no definite solution for this issue
Seems to idle at 1500 when engine is nice and warm and I am coming to a stop. After few seconds of holding break RPM drops to 725. I think that I am wasting extra fuel with my RPM jumping up and down (1500-2000 in the morning). I did a datalog and it showed that my timing gets way advanced when I relese accelerator in Neutral and that what contributes to high rpm but I guess it supposed to :-(
We can probably get better economy if we can figure this one out.

blazen351

I've got a manual tranny too, but I don't get this, mine just drops down to 750 or so RPMs and stays there until I start to go again. in fact sometimes I wish my car reved a little faster when sitting idle...Maybe I just do something different, but I don't think you can say it does it to ALL 5 speed mustangs. Good Luck figuring it though.