Hey all. Ive got a major problem, that didn't start as one. I bought a 95 chev fullsize w/a 4.3 vortech v6. Ive known the truck for a long time, and its had a characteristic knock for as long as I can remember..

Well, a few days after I got it, I found the knock was "more prominant" towards the bottom, passenger side of the motor. It very much sounds like two metallics hitting against each other.

Now a week after I get the truck the knock progressivly gets worse over the course of 3 weeks. At first was being faintly noticed from outside the truck, is now heard in the cab, under the hood, a good distance outside, and even out the back of the exhaust!

Also, as a side note, when turning the motor off, you can actually hear what sounds like something actually falling back into a resting position inside the block!

Well, last week, I left my truck parked, then come back to start up and head home. It stumbled to an idle, and when put into gear, was surging and shaking. I try to exit the parking lot and it is missing horribly.

Ive thought it was a lifter for the longest. im told it could also be a wrist-pin. But, is this what would happen if the lifter actually ate the lobe off my cam?

If so, why would it happen without warning, between startups?

I need some opinions and any help would be greatly appreciated!

 

Well assuming it has roller lifters that pretty much eliminated wiped cam lobes plus if that were the case it wouldnt me a heavy knock it would be more of a tick. I suspect you have a problem in your bottom end. To be sure though pull one spark plug wire at a time (with insulated pliers) and see if you pull one and the sound changes. If it does you have a problem in the bottom end on that cylinder. If not well look into other possabilities.