5.3 GMC vibration / shuddering

Stg2Suby

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Neighbours 2015 GMC 1/2t with the 5.3 has developed a problem, engine vibrating at all RPM, almost like it dropped a cylinder. Very rough at idle. No codes thrown which is odd, no CEL or codes on the scanner. Went for a quick drive around the block and it really shudders. Any ideas, inherent issues etc? It did flash the CEL and the traction control lights on for a bit on the test drive but no stored codes.
 

snowcannon

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Neighbours 2015 GMC 1/2t with the 5.3 has developed a problem, engine vibrating at all RPM, almost like it dropped a cylinder. Very rough at idle. No codes thrown which is odd, no CEL or codes on the scanner. Went for a quick drive around the block and it really shudders. Any ideas, inherent issues etc? It did flash the CEL and the traction control lights on for a bit on the test drive but no stored codes.
Had the same problem once. Was a dead spark plug.
 

Caper11

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I thought that was a chev thing, mash the throttle and the engine shudders like it says “ what are you doing to me”?



I agree on the spark plug. Try spraying the plug wires with a fine mist spray bottle as well.
 

Stg2Suby

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He managed to get it scheduled in to dealer first thing tomorrow, will update when I find out more. Thanks for the replies. What does misting the plug wires do, easy enough to try..
 

snowcannon

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He managed to get it scheduled in to dealer first thing tomorrow, will update when I find out more. Thanks for the replies. What does misting the plug wires do, easy enough to try..
If you get zapped you know plug is not getting full juice?
 

Stg2Suby

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He said he was accelerating fairly hard onto the highway yesterday and it suddenly stumbled and since then it's had the vibration & shudder. Truck is in the shop now so I'll update once I get more info on what happened. Thanks for the comments.
 

Stg2Suby

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Well turns out tex78 is closest - problem lies right in between the pushrod and cam lobe. Whats the issue with collapsing lifters nowadays, dodge 5.7 has the same thing? Not like hydraulic lifters are new technology.
 

tex78

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Well turns out tex78 is closest - problem lies right in between the pushrod and cam lobe. Whats the issue with collapsing lifters nowadays, dodge 5.7 has the same thing? Not like hydraulic lifters are new technology.
If it's 1-7 or 6-4 cylinders they are the afm deactivated cylinders

Very common, and probably once apart you will find cam lobe is ate off that lifter


It's the new sh! T oil, no zddp in it
 

Zrock

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Possibly fuel filter

Ill agree on that one.. had the same issue on my o3. Previous owner did exceptional maint on the truck but seem the shop doing the work never changed the fuel filter but billed him for it.. Was just about plugged off
 

tex78

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Ill agree on that one.. had the same issue on my o3. Previous owner did exceptional maint on the truck but seem the shop doing the work never changed the fuel filter but billed him for it.. Was just about plugged off
Except a 03 had a fuel filter outside the tank

2006 and up have no fuel filter outside of the tank

And the op truck is a 2015, sooooo
 

Anvil1010

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If it's 1-7 or 6-4 cylinders they are the afm deactivated cylinders

Very common, and probably once apart you will find cam lobe is ate off that lifter


It's the new sh! T oil, no zddp in it

Is there an additive with zddp in it that a person can add?
 

Anvil1010

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I just looked this up on the interwebs and I see that a person can buy an additive with this in it.
I had never heard of this before. Interesting.
 

DaveB

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ZDDP is intended for old school flat tappet motors. A roller cam should never "eat the cam lobe" Adding ZDDP isn't going to fix the issue with the GM AFM lifters. Hopefully the OP's buddy's truck is under warranty still....otherwise, get out the wallet.
 

tex78

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ZDDP is intended for old school flat tappet motors. A roller cam should never "eat the cam lobe" Adding ZDDP isn't going to fix the issue with the GM AFM lifters. Hopefully the OP's buddy's truck is under warranty still....otherwise, get out the wallet.
I still think it's the cause of the cam-lifter issues

That 0w20 oil is piss water cold and even thinner hot
 
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