p0300 misfire 2008 sierra 5.3

[Pharaoh]

my scan shows misfires on cylinder #2 & #4 also have sir codes B0081-71, u0155-00, u0170-00 and EBCM code c0561-71. I am getting spark at the plugs, pulled the #1 & #2 plugs and they look the same, changed them less than 2 months ago as well as plug wires. not sure where to look now. if i unplug the coil on the #2,4,6,8 it does not seem to affect the miss. i'm no car tech just a home doityourselfer. lol any pointers i would greatly appreciate

 

[tmurphyxzy5q]

So, if you have a miss on these two cylinders, and disconnect the control wires/connector from the coils, and it runs the same, you apparently have bad coils. If replacing those doesn't do it then I hate to say it, but the ecm's control signal could be interrupted via any number or reasons. Try swapping the coils to see if it follows the coil.

 

[Pharaoh]

thanks for the reply tmurphyxzy5q, after trying to figure it out on my own i took it to a garage for them to figure it out turns out i have major engine damage so i have to have a new motor.

 

[98trck]

maybe you should get a second opinion, unless you know and trust this garage
PETE