Does a bad fuel pump do this?

Ok, if I pour a little gas down the throttle body I can get the blazer started and it will run. If I come back 30 min later it will start, but after it sets all night it won't start unless I again pour in the gas. My question is,if it's a bad fuel pump wouldn't it not be pumping gas? :banghead:

They can be bad and they can be weak and they can have other problems.
First thing is t get a fuel pressure gauge on it and check the pressure.
What year and engine and engine code?

Yes, but won't any of those symptoms require a new pump? 1997 S10-Blazer 2/DR. Don't know about the codes.

Many no start problems can be other things besides fuel pump.
First step is to check the fuel pressure.
V6 or a 4 cyl engine? or 8 digit in vin no.?
If a 4.3 v6 here is the guide lines.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

A weak battery will cause the no-start you're describing. With a weak battery the starter takes all the current and doesn't leave enough juice for the fuel pump to reach max fuel pressure. After the engine is started the battery will charge up enough for a warm start. Take it to AutoZone, etc. and have the battery checked with a load type tester.

In my case it was a bad pump. Mine has gone out three or four times since I have owned the truck (bought five years). Check you pressure, check you power at the pump. If the pressure is below 60psi you will probably need to change it. Its about a days work, best if you can get a second person to help.

Good Luck!!!