1997 Chevy Blazer wont start without starter fluid

When the truck wont start, bang on fuel tank to shake the pump. If it starts, replace fuel pump. 60 psi is what you should see with good pump. Less than 55 it wont start.

could be low compresion

It drops when it is turned off through the return the pump might be getting weak If you keep using the starting fluid you will blow the intake off of it or it will get hooked on it and won't start without it.

Do you the 4.3 l vortec with Central SFI fuel injection system ? On these the fuel pressure regulator is under the top part of the intake manifold , They like to leak ! Leaking Fuel Pressure Regulator

Mine did that when the fuel pump needed to be replaced. Try this a mechanic friend told me this once to basically save my starter. Turn the key to on (only far enough for the radio to come on) count to like 15 or 20 turn the key back to off and then go ahead and start it up. It sounds stupid, but it got the Blazer to turn over until I could get it brought in for the fuel pump to be replaced. I hope that helps you.

try replacing the fuel regulator,or is the oil cap on tight?the fuel regulator works on base vacumm

I would think you have a faulty coil

it could also be a problem with the fuel system could be a couple jammed up fuel poppets that arent gettin fuel into the manifold i would take it to a shop unless you really know what your doin

need to check your fuel pressure...pump may be running , but not putting out enough pressure

Sounds like fuel filter is stopped up or fuel pump is going out