I’ve got a 2008 tahoe ltz 5.3 and I’ve been having a misfire problem on cylinder 7 and smoking.. I’ve replaced the coil pack, spark plug and fuel injector. It smokes white/blueish and my coolant is clean also oil is clean. sometimes it doesn’t smoke and then other times it starts too again. i haven’t tried a leak down test (yet) but im wondering if anyone up here has had the same problem with these year models. Also it doesn’t have any blow by. The head has been replaced recently. Could it be a ripped head gasket? Bad valve seals? Hoping it isn’t anything too bad being internal considering i want to install a cam in it but i wanna figure this out first so i know everything i have to order. Thank you in advance

 

Plug Wire "booots" need to be greased.
Did you do this ?

 

My 2019 is actually doing the same exact thing, it dropped a lifter. Im putting a dod delete kit on it from Texas speed and im also while im at it putting in a new torque convertor, trans filter, and trans thermo bypass. Transmission isnt giving me problems but were pulling the motor to put the dod delete kit so its just gonna be one of those while im there reassurance things. For the record my 2019 is the 2018 body style so anything I purchase i buy for the 18. Its not the new body style.
pull your driver's side valve cover and watch the rockers in the rear, you will see the problem.

 

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Why was the head replaced?