sounds like the timing chain rapping against the timing cover, sounds much worse cold...

is thee a tensioner? what needs to be done? how laborious is the job? common in this car

thanks for the info guys..

Well I know Don changed his timing chain by himself for $100. If you take it to a shop it will be around $500-600 I bet, which sucks since I want mine replaced. Maybe he'll chime in...I think he said he did his in an hour (with a friend...who has air tools).

make sure you get a new slack adjuster

How many miles do you have on your car?

now 99000, is this a handy-mans / backyarder job?

Just make sure it'* NOT a Conn Rod or Oil Pump Knock.
Basically you're gonna need a new Chain, Cam Gear, Crank Gear, Chain Dampner, Front Cover Gasket Set, Oil Pan Gasket (due to coolant from cover that went into oil pan when removing it) & LOF (Lube, Oil, Filter).

Well if you can get a hold of the GM Tool to re-align the Crank Sensor it is. you're also gonna need a Ballancer Puller too (GM Tool again). :? The Series II'* are a little bit harder to tear apart than the Series I'* were. You're gonna need to support the engine too while doing this, the Front Mount has to come off as well.

are you sure it'* the timing chain it could also be the harmonic balancer!

That'* because the Balancers on Series I'* are NOT press fit like on Series II'*!