Ignition or Fuel Pump?

I really didn't start having this problem until this winter, but only sometimes when I try to start my Blazer it wont start and I will get like a loud whining noise like it wants to start but wont. But if i immediatly turn if off and turn it back on it fires right up. Any ideas? It seems to be worse is really cold wheather..

I really didn't start having this problem until this winter, but only sometimes when I try to start my Blazer it wont start and I will get like a loud whining noise like it wants to start but wont. But if i immediatly turn if off and turn it back on it fires right up. Any ideas? It seems to be worse is really cold wheather..

You might want to try putting the key in the "run" position for 5 seconds before trying to start the truck. This will let you know if it's a fuel pressure problem,as it will allow the pump to build-up pressure.

You might also want to list the year,model, and engine type. Just might
help you get a quicker response from someone whose had a similar problem.

Sounds like your truck isn't holding the fuel pressure after it sits for a while. You need to check your fuel pressure system. I believe the instruction is in the how to section on this forum.
SC