Idle hunting...

jrollf

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OK new one for me. Today I noticed that when I let off the throttle, it drops below idle RPM, then hunts around the set idle for a couple seconds before finally settling to a constant RPM. Kind of like it wants to start loping but then decides to even out.

Any thoughts? I haven't made any recent adjustments.

I took a quick video of the tach, I reved it up a little twice and then take my foot of the pedal:

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1993 F350 Crew Cab Dually
7.3L IDIT with a Banks Sidewinder
ZF 5-spd manual transmission
 
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Thewespaul

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Low fuel pressure or could be you’re getting some air intrusion, but even just a bad tank of fuel can do this. Try some hot shot extreme see if it clears up if you’re not seeing bubbles out the return line and your post filter pressure is good.
 

jrollf

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I'll start looking into the suggestions... hoping air intrusion as that would likely be a cheap fix.

I just replaced the lift pump and filter a month ago and pressure checked good then, and the IP is only a few months old from CDD, so hopefully no issues there.
 

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