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Recentley I was driving my 02 zo6 and i punched it in 1st gear, when i shifted to 3rd, the motor kind of stopped for a second and then accelerated like normal. Traction control WAS off. When I got down to speed (10-15mph), the car sort of bogged and started to shake heavily. I pulled over and thats when I heard a loud "click click click click" coming from under the car near the motor. I pulled up my codes and there was a "p0300 h c" random misfire code. I checked the clutch and everything looks ok. I switched my spark plugs and wires around, also gapped the spark plugs without success. A local shop (corvette experience) said it sounded like broken lifters. I also checked my valve springs and none are broken. The ticking noise gets louder and faster when engine rpm increases. I will attach a short sound clip from under the car soon so please listen and let me know what you guys think it is. Any input will be appreciated! thanks!

 

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1. where does the noise sound like it's comming from?

It's hard to tell from the sound clip thoe,
The sound clip is a great idea,

I'd pull the valve cover and see what's going on

It could be a rocker or a lifter

Hard to say without looking in there

Bon
 

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they are notorious for broken valvesprings, and i have seen several rockers break
 

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I definitely agree that it sounds like valvetrain noise:

broken springs
lifter issues
bent pushrod
broken rocker


take a piece of hose, or a really long extension and use it as a stethoscope, this will give you a better idea of the affected area(it will be loudest there). Once you have a better idea of where the noise is, start simple and work your way down. you can not get to the lifters without removing the head. A lot of times in these motors if they get over revved, like when shifting, the valvetrain will float for a second, a piston will smack a valve and that force will travel all the way to the pushrod, causing the rod to bend. On a stock motor, the pushrods are the weak link. Dont replace them with chromoly, you want the pushrods to be the weak link. To check the pushrods, clean them off and roll them across a piece of glass. If they wobble theyre no good.


as far as questioning my knowledge and experience, im an ASE certified tech, ive built many of these engines and I am the lead tech at GMMG Inc
 

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:agree:
I'd be suspisious of a bent pushrod, probably from float. One other thing it might be though, the rockers have been known to spit thier bearings out of the trunions. I wouldn't run it to much until you find the source.
 
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