Engine turns but wont start
 

So I go to start my car for work today and it would not start. The battery is working and the starter worked. When I let off the key the engine seemed to turn over but did not catch and immediately died. It was giving me problems earlier with surging and laging when I went to accelerate.

Fuel pump died I'm thinking? Thought?

Can you hear the fuel pump run when you turn the key to the on position?
check for spark?
check fuel pressure?

Be sure to check the fuel pump, and the relay for it.

To check the fuel pump turn the ignition on (don't crank) and you should hear a whinning sound coming fuel tank. If you don't then take some gas in a small cup and pour down your throttle body and try to crank it...if it cranks=bad fuel pump.

What year, make, model, engine?

If it tries to run when you let off the key, it could be the contacts in the ignition switch are not making a good connection in the "crank" position. Ignition switch problems are fairly common on these vehicles, especially 1997. You'd need to do some testing to make sure the ignition module and ignition coil are getting good, constant power when cranking. Do you have a test light or DVOM?

It is a 2000 s10 Blazer with the 4.3 Vortec engine.

I have no means to test it but a friend who is a mechanic is going to come over and take a look at it when he gets the chance.

Anyway I gave it a shot last night after work and on the first try it turned but died out when I left off the key again. I also though I may have heard a pop noise from the engine. Anyway, I tried again and it turned over and ran. This morning I tried it again and it turned over on the first try. I drove it about a mike after it warmed up and seemed to be working fine.

Any ideas?

You need to determine if it's lacking spark or fuel when it acts up. Checking for spark at the coil wire, where it plugs into the distributor cap, will determine if you have constant spark while cranking. Needs to be a blue spark, not orange, and able to jump a half inch gap to ground.

Same problem
 

2003 blazer LS 4.3. Thursday, started fine like it has since I got it last summer. Turn the key, it'd barely crank and it starts. Friday afternoon, no go??? Turns over fine , but no start. As I release the key to "run" it sounds like it's trying fire up but doesn't. I can hear the pump prime when I first turn the key, but nothing. Also figured I'd smell gas after trying a few times to get it goin but nope not even a hint of raw fuel. I'm thinking filter and or fuel pump. Towed to my mechanic but only had an hour 45 till close, so hopefully Monday they'll find the problem.

First test is fuel pressure leak down. Second test is the strength and regularity of spark at the plugs.

George

Update
 

been scouring YouTube and came across one video that fits my situation. Testing the coil , it only sparked briefly and weekly when the key was released to run. Which is what mine seems to doing as it attempted to fire up weakly when I released the key. Ignition switch module was the problem. I'll find out Monday but my money is on the switch module.