Well after a good run, it seems the truck is fighting a Cylinder 7 misfire that came up today. I think my son hasn't been diligent enough with monitoring oil levels based on the fact it was 1.5 quarts high and there is a p0521to be
2011 CHEVROLET Silverado 5.3L V8 3GCPKSE3XBG305530
Odometer: 257,790 mile
P0307 Cylinder 7 Misfire Detected
P0420 Catalyst System Efficiency Below Threshold Bank 1
P0521 Engine Oil Pressure Sensor/Switch 'A' Range/Performance
I'm noticing a sporadic tapping metallic noise at idle, where do I go from here? Thinking of pulling the valve cover an taking a look. I'm guessing broken push rod, lifter, or rocker arm.
What is worst case scenario?
What is best case scenario?
Most likely you have a spun lifter, using the starter relay with the key off, spin the engine over. Make sure not to jump the wrong terminals as it could damage the ECM. Vlom Must be on for this test. While it is spinning watch the suspected rocker move. Make sure that it rocks at least 6 to 7 times before you let up on the starter. If the one rocker stops moving before then, it is getting fed oil pressure and is likely spun. However, if two rockers stop moving then you likely have a leaking VLOM. You can determine a spun lifter by looking at the side of the lifter. To see the side of the lifter you need to pull the VLOM and clean out the oil tower of the suspected lifter with cleaner and shop air. Once cleaned you can look down the oil tower and if you see a hole in the lifter it is not spun. If however you see only shiny metal or a flat surface then the lifter has spun due to a bad plastic lifter guide. When this happens you will need to replace the camshaft and all lifters. This would be a good time to do a full AFM/DOD delete where you remove all AFM components and replace them with non AFM components.
I do now offer AFM delete kits for select models. Be sure to check my website for your engine.
https://www.crazedperformancerepair.com/afm-delete-kits