i have a 2000 silverado 5.3 2wd. engine has 50K on it.i have had no issues until i installed the 90mm throttle body and TBSS intake. last night i was driving my truck to a friends house and i got to the stop light and the engine died. i started it and it was a hard start. i have been having vacuum leak issues so this was no surprise. it finally starts and i hear the worst metal on metal sound. it sounds like a spun rod bearing. but here is the kicker that has me confused. if i spun a rod it should be firing that cylinder. but the engine is shaking and backfiring like its not running a few cylinders and the metal sound is off and on but the misfire is constant. im beginning to lean toward a broken rocker or valve spring. any thoughts?

 

Moving this to the correct section.

 

sorry about that.

 

pulled the valve covers and all valves and springs are in the correct spots. im going to pull the pan tomorrow and check for a busted piston skirt or some other damage.

 

Vacuum issues? Maybe you ran a cylinder too lean and burned it up?

 

would i get a clattering noise if i burned up a piston?

 

sorry, that is not good.... Can you get a video of it?

 

Why didn't u fix the vacuum leak ? Maintenance is a big factor that a lot of people forget to but the most important one

 

i had been working on it. i was driving it to see if it was fixed. figured i would pick up my tools across town while i was at it.

 

This is what a burned piston looks like, rev up the engine and it sucks up oil. Click on picture for video...