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Discussion Starter #1
First post. I've searched high and low for symptoms exactly like mine with no luck. If there is a post you know if I'd love the link. Anyways, so I've got an '08 f250 that just recently developed a pretty odd idle. It happens only when idling in park or when my foot is on the brake while in drive or reverse. my truck typically idles in the range of 640-670 rpms but lately its been spiking up to around 800 rpms then down to less than 600 then back up again. I doesn't always do this but I can't seem to to find anyone who has this problem. Also, this problem only occurs when I'm at a stop light, idling backwards in reverse, or slowing to a stop. If I am driving at a normal speed with the RPM constant there is no stutter at all. I'm hoping i don't need injectors because I'd really rather not spend the money but any suggestions on a diagnosis would be great. I've got a mechanic that I trust here in Katy but he's expensive and I'd like to see what I may be able to do myself first.
 

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hmmm

I will be honest with you I too have the same problem. Monitored Injector pressure on my Mini Maxx and everything seems good. TYhe truck just goes into a "High Idle" state, even though it isn't a real high idle. My idle goes up to the same as yours but doesn't go back down until much later.

I change my fuel filters at regular "Heavy duty" service intervals at Ford. They basically do all my servicing. The truck has been doing this way before upgrading to the mini maxx and does it so rarely I can never reproduce it.

My truck currently has 80 000km, F-350 2009 PSD straightpipe Airaid intake with mini maxx tuner set on Medium - Wild.

Dan


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Discussion Starter #4
I've changed the filters every 10k, and yes the fuel filters were replaced a couple weeks before symptoms.
 

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Discussion Starter #5
i'll drain the fuel water seperator but I really don't think that's the problem. i too have had to high idle "surge" but it goes away with a quick tap of the throttle. p.s. i have installed the flo pro egr delete with the elbow, and done the dpf delete with 4" downpipe back mbrp exhaust and hs mini maxx programmer.
 

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Discussion Starter #6
drained water separator and that didn't do anything - filters were replaced a little over 2k miles ago. anybody have any other suggestions? is there anything i can monitor on the mini maxx to rule something out?
 
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