1999 chevy tahoe flashing check engine light and noise

Disconect the fuel fed line into the fuel lug that runs the fuel injectors,check for pressure ther,also try to listen for the fuel pump kick in when the ignition is on possition.

Two things:

First, are you aware that your vehicle will only have power to the fuel pump for about 2 or 3 SECONDS before engine start-up? Then the engine must be running for it to have any power beyond that?

Second, is the "Security" light flashing on your dash? If so, you have a security system problem. There won't be any power to the fuel pump.

Your fuel pressure can be checked by connecting a fuel test gauge up to fuel test port which will be located on the fuel rail at the back of the engine on drivers side next to the distributor.Your fuel pressure should be 60-66 psi with key on engine off.If its not within these specs then replace the fuel pump and filter.

without hearing exact noise it is hard to diagnose. these vehicles had a normal cold start knocking noise due to the low friction rings used allowed piston some extra movement. when carbon builds up on pistons it gets worse will go away after about a minute running. it does not affect life of engine or performance. i think this may be noise you hear. or possible it is a lifter leaking down and taking a while to pump up

Check the connections on the battery and where they connect to the engine/starter. Do you get any inside lights at all?
Check the voltage on the battery - should be 12 volts (engine off)

check fuel pressure. If its marginal then replace the pump. These trucks are touchy on fuel pressure. Just a couple psi low and they do exactly this. In the morning cold is when you need max fuel. Be sure to replace the harness also as these tend to lead to repeated pump failures when faulty, which is pretty common

I have seen this problem on many gm trucks including my own 1999 chevy tahoe with the NP246 transfer case model the rear out put bearing has a plastic cage the falls apart and or the clip holding it in place shatters causing this noise you can inspect this by removing the rear drive shaft and with a flash light look into the transfer case tail shaft to see if every thing is intact. also this type of transfer Case is known for the drive chain to stretch and hit the inside of the case housing start by checking the bearing first.

I'm assuming that by turning over, you mean that the engine fails to turn with the starter . Check your battery for 12v and make sure all connections are clean and secure. If battery has less than 12v charge it and check the charging system after re-starting. Lights and radio do not pull the same amperage as the starter and may not tell you much about battery condition. If you have full battery voltage, check the starter for 12v at the battery connection and the small (trigger wire) for 12v with the key turned to start position. If you have both, likely starter has failed.

clunky= internal engine repairs have a compression test done on it

Go to Advance or Auto Zone and have them run an obd scan on it and it will pin point why your light is on and could solve your problem. This is often done for free.