[tommie]

on the coolant temp sensors that i have had experience with going bad, they were usually making the computer think the engine was too cold, and the computer was feeding the engine too much fuel.....

have you taken the air cleaner off to watch the injector spray pattern when you are trying to crank the engine? or when it is running?

i have done this before and have seen a very rich spray pattern before (coolant temp sensor)

what do the spark plugs look like? do they look like they are fuel fouled? or are they clean?

sometimes these things are hard to diagnose over the internet.... the best bet would be to check the fuel pressure and report back (search, but it is hard, and you need an adapter to make it work)

i would also search and find posts from chevy tech about checking the coolant temp sensor with an ohm meter, and report back on that also...

another thing to check would be for proper spark...... what you are describing could be cause from a weak ignition coil also....

these things are easier to diagnose in person...than over the internet....