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02 4.8 silverado surging??

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Old 07-03-2020, 12:31 AM
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Default 02 4.8 silverado surging??

Truck has a little surge in final drive gear when trying to accelerate slowly or going up a hill. If you get it to down shift it goes away. changed the coils with known good ones. I logged the misfires to see if I could see anything and when It does it all the counters stay at 0. When I drove the truck to my house originally it did not do this. I am going to take my dads y pipe with his cats and see if maybe with the truck being drove for who knows how long before I got it with misfires clogged the cats.

Threw both knock sensor codes today

trans does not feel like it is slipping at all as there is no rpms flare while driving it. Hoping if worse case it may be the tcc soleniod as that does not look to hard to replace. I just do not think that it just went out though.

Idle bounces from 550 down to around 430 in drive sitting still. Not as bad in park but it is noticeable.

tcc slip rpm.
In high gear when it starts to surge the tcc rpm is around 1-5 varying. when you step on it and you can feel it down shift and the tcc rpm goes up to 330-400.


From what I saw fuel pressure is around 52 ish driving even during the surging but when you let off the accelerator it drops to 42. I am going to be swapping the cats tomorrow as I have been fighting the back 2 bolts on the back of the y as there started to spin in the pipe. Just go those out.

any help?


missfire video

fuel pressure at idle

tcc rpm slip video

fuel presure while driving video

idle video (in park to drive back to park)
Old 07-06-2020, 06:53 PM
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Ever cleaned the throttle body before?
Old 07-06-2020, 11:34 PM
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no have not.

had a tree fall on the bed the other day so I am kinda sick of the truck atm.
Old 07-21-2020, 10:53 PM
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Update, I replaced the knock sensors and harness front sensor had water to the top of the valley plate. I used oem sensors and it is almost all gone on the surging. Maybe once to twice a day it does a little small surge that is hard to notice. With the bed getting crushed I have been trying to find a decent white long bed. While I am replacing it if I ever find a bed I am going to swap to a 340 drop in pump for future plans.

I think that the small surge I see is from the injectors. Have not been able to find a trustworthy place for replacements or cleaning.



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