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Discussion Starter · #1 ·
I've noticed while idling today and yesterday an intermittent hiccup/stumble idle fluctuation. Happens when engine is at operating temp and with or without my high idle switch on, in park or in gear. This is very intermittent so far, and no check engine light. Truck runs and starts normal. Took out on highway=runs good/full smooth power and boost levels, no smoke at all when this happens idling. I am thinking its possible my EGR valve is starting to act up, but I'm not sure. Tonight it ran fine without any hiccup/stumble at idle. 52k on the truck so far. Any input is welcome.
 

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Discussion Starter · #2 ·
Well, I guess I'll answer my own question. No codes or rediness failure codes when checked with my scan tool. I was told, when the egr valve is intermittently not seating closed, the trucks computer sees this by the potentiometer reading from the egr valve, it sends rapid voltage pulses to the egr valve to try and seat it closed. That would explain the stumbling at idle. I guess its time to clean the egr valve, and hopefully thats all it is.
 

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harry6.0 said:
I've noticed while idling today and yesterday an intermittent hiccup/stumble idle fluctuation. Happens when engine is at operating temp and with or without my high idle switch on, in park or in gear. This is very intermittent so far, and no check engine light. Truck runs and starts normal. Took out on highway=runs good/full smooth power and boost levels, no smoke at all when this happens idling. I am thinking its possible my EGR valve is starting to act up, but I'm not sure. Tonight it ran fine without any hiccup/stumble at idle. 52k on the truck so far. Any input is welcome.
well I see you have an 03 truck if its not the egr check the icp plug or connector there maybe oil present if so the icp and icp pig tail would have to be replaced,Ive seen this happen with a rough idle problem,It may not be the fix but worth alook.
 
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