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Stumble & Hesitates
Well this weekend on way home on the freeway I noticed the truck kinda hesitate or stumble as if it was gonna die for like a split second so I slow down to about 60mph and while I’m watching the gauges I noticed my tempature gauge drop all the way down to 160 I noticed that it does this everytime it stumbles or hesitates now that its becoming more frequent. I also noticed my gas milage has dropped drasticly since all of this. I do know that I need to change out the knock sensors but I don’t think the knock sensors would cause this problem or will it? I checked the fuel pressure it was good. This is starting to drive me crazy as its getting more constant and harder to start it seems like everyday. This is on a pretty much new 5.3 only 5k on it and started a week after I did the tbss intake swap. I’ve attached a video if someone can steer me in the right direction.
Stumbles & Hesitates - YouTube |
no trouble codes?
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Originally Posted by nonnieselman
(Post 5088063)
no trouble codes?
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Tried checking for a vacuum leak?
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Originally Posted by nonnieselman
(Post 5088073)
Tried checking for a vacuum leak?
Not yet ill check that out |
On what I have worked on, a bad vacuum leak will cause a high idle. I figure if it was severe enough it would trip a fuel system lean code. When my knock sensors went bad it would stumble as soon as it hit power enrichment. When I had the power enrichment tps set to 55%, this was very noticeable while cruising. It would pull timing as soon as it started enriching. Depending on your tune, this could cause the stumble you feel. The gauges flickering make me want to say pcm ground though.
If it were my vehicle, I would hook a scanner to it and see if the stumble and timing being pulled are synced. My guess is they are. |
Originally Posted by kelsey_canard
(Post 5088218)
On what I have worked on, a bad vacuum leak will cause a high idle. I figure if it was severe enough it would trip a fuel system lean code. When my knock sensors went bad it would stumble as soon as it hit power enrichment. When I had the power enrichment tps set to 55%, this was very noticeable while cruising. It would pull timing as soon as it started enriching. Depending on your tune, this could cause the stumble you feel. The gauges flickering make me want to say pcm ground though.
If it were my vehicle, I would hook a scanner to it and see if the stumble and timing being pulled are synced. My guess is they are. Thanks ill check that out tonite |
2 Attachment(s)
well I got a log hopefully can point me in the right direction. cant really tell if its pulling timing or not but I did notice that the fuel system is cutting out when this happens but not causing it to cut out:bang:
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Originally Posted by way2much_01
(Post 5091248)
well I got a log hopefully can point me in the right direction. cant really tell if its pulling timing or not but I did notice that the fuel system is cutting out when this happens but not causing it to cut out:bang:
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Originally Posted by kelsey_canard
(Post 5091355)
I don't have efi live or I'd take a look at that for you. What do you mean when you say the fuel system is cutting out? Does it stumble when the fueling mode switches to open loop?
That's exactly what it's doing... |
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