Cylinder Misfire

[jwroch]

I have a 2014 Silverado LTZ, with a 5.3L engine. There is approximately 145,000 miles on the engine. I have a misfire on the #3 cylinder. I have replaced the induction coil on the #3 cylinder, but I still have a misfire on this cylinder. My mechanic says that the lobe on the camshaft is worn and the camshaft needs to be replaced. 

I would think that if the lobe on the camshaft is bad then other lobes would also be bad, a defective camshaft.

 

Has anyone else had this problem? Does anyone have any suggestions as to what might be causing the misfire.

 

Thank you in advance for any advise the you can provide.

Julian.

[Snowcamo]

Try the wire and plug first. Then a compresson check

[jwroch]

Thank you for your advise. 

I will check the wires and compression out.

Julian.

[newdude]

2 hours ago, jwroch said:

My mechanic says that the lobe on the camshaft is worn and the camshaft needs to be replaced. 

I would think that if the lobe on the camshaft is bad then other lobes would also be bad, a defective camshaft.

 

 

 

Nope.  That just means cylinder 3 had a lifter probably spin in the lifter bore or in the lifter retainer and then pounded away at the cam lobe.  

 

Swap a wire, swap the plug.  If it's still there, compression check.  I'd then maybe pull the rocker cover and pull the pushrods and valve springs out, see if they are bent/broken.    

 

Also, only because I've seen it happen.  Cylinder 3 is on the driver's side, second from the front of the engine.  So if you are leaning over the driver's fender looking at the engine bay, cylinder 1 is closest to the radiator, 7 is all the way at the firewall.  

[14burrito]

Coil, wire, spark plug, compression check, leak down, injector swap

[JONBLARC7]

Problem with injector swap is.  You have to pull all the injectors on that rail at the same time.  Then put all new O rings back onto each injector.  And that is a huge pain in the ass.  I've done it a couple time on my truck.

 

If want to go that route let me know and I have a really good video saved on how to do the seals without any speacial tools.

[Beer Belly]

My '15 Sierra early on had a misfire cyl 7.....ended up being Lifter issue, replaced the entire bank under warranty