So I bought a 2000 zr2 and the guy gave me a list of things that were done to the truck, one of them was a full tune up but it doesn't say brand of parts. I am getting bad mpg and it seems to lack of power.

Did a fuel pressure test and it had 56 psi and dropped to around 40. So I know it has a fuel leak somewhere, where should I start looking to change things?

And should I re do the tune up with as delco stuff?

 

I don't know what spec says but the fuel pressure doesn't sound all that bad. The drop is probably because your filter leaves something to be desired.
4.3's seem to be a little picky about spark plugs as well as cap and rotor. It's ideal if they're Delco. I really wouldn't expect that to have too major an effect on performance if it's a recent tune up.
It sounds suspiciously like the catalytic converter may be on it's way out. If you hear a rattling noise coming from it, that's a pretty sure sign.
One thing that you can try is removing the O2 sensor and giving it a quick blast down the street. It'll be loud as all get out but if there's a large difference in performance, you just might have too much back pressure on the exhaust.
It could be a lot of other things but that's one that I'd investigate.

 

I agree about the plugs however, that's too much of a drop in fuel pressure. I would suspect a leaking fuel pressure reg or injectors. You can try to look down the throttle body with a flash light, if it looks clean or shows signs of washing you know you have a leak.
Or you can replace the fuel filter and re test.

 

This is going to sound like a dumb question, but where are the injectors? I was under there and I couldn't for the life of me find them, lol.

I was told I wanted it to be around 65 initially then not drop below 55 in ten minutes. So I started where I wanted to end and it just kept going down lol. Could this be fuel pump related? From the list I had the previous owner never changed that.

I'm not going to do another tune up until I am out of options as honestly, the plugs do not look fun at all to change.

What do you mean signs of washing in the throttle body?
And all I need to do is pull the air intake off and I should be able to look right down the throttle body yes?

 

Your fuel pressure is too low and the leakdown is excessive. Key ON, engine OFF, fuel pump running: fuel pressure must be 60psi to 66psi and must remain above 55psi for at least 10 minutes after the pump shuts off. Your results indicate that there's a problem with fuel delivery. They do not tell you what the problem is, only that a problem exists. Next step is modify the pressure tester so it will connect to the fuel filter outlet. All fuel pressure and flow must "dead end" at the tester. With the fuel pump running, pressure must be 73psi to 108psi and must remain above 55psi for at least 10 minutes after the pump shuts off. Results of this test will tell if the problem is in the tank, or in the plenum.

 

Thanks, is there a right up somewhere that anyone knows about how to modify it to fit the fuel filter?

And the fuel filter is inline I assume? Running along the frame rail somewhere?

Really appreciate the help, would like to diagnose this and have the weekend to fix what I can seeing as I am off this weekend.

 

Here's one that I made a few years ago. It connects inline at the fuel filter, (on the left frame rail) It will check: regulated fuel pressure, system leakdown, maximum pump output pressure, and fuel pump leakdown. It can also isolate the fuel pump from the rest of the system for diagnosing leakdown in the plenum. Cost was around $40 or $50 and maybe 10 minutes to put it together.

 

Found the fuel filter, thank you. Where did you get the end that attaches to the outlet of the filter? Is it something I can buy at a parts store?

 

Here are the two fittings you need. You'll also need fuel injection rated fuel line, and some good hose clamps. All of the other stuff you can get at Lowes/Home Depot etc, a ball valve, a gauge, and some brass adapters.

Buy Dorman - OE Solutions Steel Body Fuel Line Connector 3/8 Inch 800-121 at Advance Auto Parts=

Buy Dorman - OE Solutions Steel Fuel Line Repair Kit 3/8 Inch x 12 Inch Double Bead Line 800-155 at Advance Auto Parts

EDIT: Make sure you set it up as in the image, or you won't be able to check maximum pump output pressure when you close the valve.

 

Thank you, I already have a fuel pressure tester, I can, I assume just put the end on it that attaches to the fuel filter to test that before I build something from scratch?

Also here are a few pictures of my throttle body, I assume these are not what one considers clean? What would it of being clean of meant?