Tapping noise 08 suburban
So my 08 5.3 has lifter noise added cleaned to oil
let it roll on till next oil change. Then this
happened woke up to go to work the loud all day
clacking went away .. Smooth as silk but then
started ideling badly like it was about to blow turn
truck off quiet as a church mouse and still no
clacking but drive under load again misfired from
hell I was told lifters but hard to find stuck lifter
now that it runs good when not acceleating under
load ... I'm lost
Do you still have the cleaner in the oil, or have you changed it since? Gunked up lifters may not be expanding/collapsing like they should, so that might be one reason for misfiring. Collapsed lifters under load will definitely give you symptoms like yours. There is a TSB on 5.3's with AFM (Active Fuel Management) lifters collapsing/getting stuck. You can try removing them and cleaning them or just replace them.
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