I have a 2000 zr2 blazer with a 4.3 It has been really tricky to start ever since I got it. If you let it sit for awhile and try to start it it turns over a couple times before it fires. If I turn the key on and let the fuel pump run for 2 seconds, then start it , it seems to start better. Sometimes it will fire right up, sometimes it turns over 1 or 2 times first.

I know its not the fuel pump. The pump runs just fine. I put a fuel pressure gauge on it yesterday and it shows 55-60 when the fuel pump is running, but the second the fuel pump stops running the pressure drops to zero. So I am wondering why the pressure keeps dropping and if it suppose to or not.

When running the blazer runs just fine and has 55 psi or so. Gas mileage has also been consistently getting worse. I used to get 19, now I get 16. Whats the deal?

Most likely a leaking fuel pressure regulator. Remove the air intake tube and open the throttle plate all the way with engine off use a flash light to see if the floor of the intake is nice ands clean if it is or you smell alot of fuel replace the fuel pressure regulator. The other option is to use a fuel pressure guage ont the vehicle and turn the key on after pump stops runningpich off bothe the return and the feed fuel line if guage holds the pressure steady the problem is the pump. If it doesnt hold pressure it could be an injector or regulator most likely the regulator. My .02$ :grinpimp:

It is quite common for the regulators to go out on those, do the above check for fuel, if bad you have to pull the top half of the intake manifold. The regulator is inside with a spider looking injectors connected to it.

Vortechs are notorious for leaking fuel pressure regulators, you're lucky you have a 4.3, replacing the one on my 7.4 was a pain in the ass.

Alot of times the pressure will look OK when you test it but if doesnt hit the target press almost instantly it will start dying and be hard to start.