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View Full Version : 2008 lmm rough idle and bucking and jumping.



2008lmmlatham
04-15-2020, 12:59
Ok guys this is my first post here.
I have a 2008 gmc 2500hd ccsb 4x4.
When i start the truck after its been sitting it starts and runs great, but ones i drive it and it makes operating temp its takes a turn for the worst. While im driving it will start jerking and kinda cutting out, it hasn't ever died but its rough. When i come to a stop light i have to hole the brake tight or its gonna jump across the intersection. But one i park it and it cools off, and i start it back up it runs great till it gets hot again. It dont smoke or anything, i have put a new fpr on it. Was told that it has a new cp3 on it but i can not confirm that. Also put a new MAF on it. It is turned and deleted, "unsure what the tunes are but told it is efi". Fass lift pump on it, beans sump, 5in straight pipe. Also deleted the fuel filter housing.

Anything will help guys.

Thank you,
Micheal

a5150nut
04-15-2020, 17:08
You removed all fuel filtration?

Have you read the codes? And is the SES light on?

2008lmmlatham
04-15-2020, 17:29
I removed the fuel filter housing but have a lift pump with a fuel and water filter. And i have no codes with my lil scanner, and the ses light is not on

Kennedy
04-16-2020, 08:24
Why a guy would saw a hole in the floor of a perfectly good fuel tank is beyond me...:rolleyes: The head is the same whether you lift from the top or bottom.

To start check the supply pressure if the Foaminator and make sure it is below 10 psi. Also put the OE filter back on. if the miracle filters are as good as they claim (not) you should never have to change it.