I am getting low fuel pressur.
I alredy installed a new fuel filter.
So it has to be either the fuel pump or level sender, right?
Is it any other possibility it could be?

 

Is youe Blazer fuel injected or is it an older model carbuerated?
If its injected, It could be the sending unit, but if there is low pressure and the is no leak, it is definately is the fuel pump. I believe your problem is that the pump is losing pressure somehow.

I have a fuel pump problem myself, it seems to make a loud grinding noise, but I haven't lost fuel pressure at all. Seems a bit weird.

 

I work with fuel systems on aircraft and usually when we get low fuel pressure it's the pump. I know it's two different worlds, but the principle is the same.

 

It could be fuel pressure regulator located in the fuel meter block (fuel injection spider), some are replaceable. A good way to tell is the smell of raw gas in the intake manifold. Although this could also be a meter block leaking but it will let you know if the problem is in the upper intake...

 

What year is your truck and what is your fuel pressure reading?

 

I don't think it matters what year your truck is, if it has low fuel pressure, it is NOT being caused by a bad sending unit! The sending unit is strickly used to indicate how much fuel is in the tank. It has nothing to do with pressure. Like chevylover said we need to know your pressure reading in PSI and the year/model/engine etc.....to help you diagnose this ACCURATELY.

 

I would change the fuel pressure reg as 20Blazer00 stated.

My pump has been unusually noisy lately. I have good startups, but the audacity is is concerning me.

 

Yeah, anything used for indication is not going to have an effect on the gas moving through the system. There's nothing mechanical to them anyways.