So I went to start my car this morning and was greeted with a lovely knocking noise. Not the normal piston slap noise, like someone was taking a hammer to the valve cover noise. Sounds like its coming from the drivers side. Hooked up my Torque scanner and found a high count of misfires on #5 and #7 cylinders. Oil pressure was good, nothing in the oil. What do you guys think?
Thanks

2001 Trans Am 103,xxx miles
5.7L - Lid, exhaust, PP TB

 

bent pushrods?

 

That was my second thought. I forgot to mention that this came out of nowhere. Was fine last night, wasn't riding it hard, just normal driving then boom this morning.

 

What kind of lifters are you using?

 

Everything internally is stock to my knowledge.

 

You might have dumped some rocker bearings. You can either pull the valve cover or drain the oil to check although pulling the valve cover is a more reliable way to figure it out.

 

I think you should pull the valvecover.

 

I just wonder what would cause a knocking noise that loud within the valvetrain.

 

^^^^ Do this first! ^^^^

 

Odd question but did it happen to rain overnight? I've read a few posts where people left the car parked outside overnight and the cowl seal leaked and water made it way into the cylinders because of loose intake bolts. Some broke off starters, Other bent of broke a rod. I know it's not likely but many of those posts started out the same as yours.

 

As a matter of fact it down poured the night before.... And my pops said he thought it could have hydro locked as well. Tearing it down this weekend so we will see

 

Sounds like a collapsed lifter.