Green94B4C

Kinda long...sorry but I really need some new thoughts on this and I have searched all the threads already.

I am getting very annoyed with all the problems my 94 LT1 has been having for the past year. Last year, I took out the Hypertech program, removed my MSD 6AL, and the NOS fuel pump because I was going to sell this stuff. The car ran fine for a few months, then I got a huge hole in my y-pipe that caused it to run like s***. I got this fixed, but the car continued to run bad once it warmed up. It loads up and will not get out of its own way for a few seconds, then it jerks and runs normal again for awhile.
Since the beginning of the year, I have replaced;
O2's, wires, plugs,the opti 3 times, cap and rotor, fuel filter about a year and a half ago, switched PCM's with a friend to see if that was the prob, had the PCM tuned, and replaced almost every single sensor on the car.
Now today, the thing starts running horrible, and dies on me every time I am at a low RPM. It died in the parking lot at work and did not want to start back up. When it did, it made a scary knocking and hissing sound from the motor.
The car has about 95K on it and has not been running hot. I am at a loss here...is my car just dying? Is my motor about to take a poo?
Please...somebody, anybody help me out here. I love this car, but I am on the brink of driving it off a cliff.

Colin91Z

Have you tested the fuel pressure? Sounds like a dying fuel pump to me...

Green94B4C

No, I have not done that yet, but that was another idea I had in my head. What is the easiest way to test it?

Colin91Z

Get a fuel pressure gauge from your local auto parts store, screw it on to the scrader valve on the back of the fuel rails, disconnect the vacuum line on the regulator and turn the key on and look at the pressure. If you have a stock regulator then you should have ~47psi. If you have much less than that, you have a problem. If the pressure seems alright at idle, then tape the gauge to the windsheild and go drive around. See if the pressure is dropping when the car starts to act up.

Colin91Z

Here I found this courtesy of Shoebox

This pic should help

http://shbox.com/1/fp_reg.jpg

Green94B4C

Thank you very much for the help
I do have an aftermarket regulator on it though, so do you know what kind of psi reading I should get if everything is ok?

Injuneer

For the pressure specs:

Start the engine. Remove the vacuum compensation line from the fuel pressure regulator, and plug the opening in the vacuum line. The fuel pressure should read 43.5psi. GM accepts any value between 41-46psi.

Reconnect the vacuum line. Fuel pressure should drop proportional to intake manifold vacuum. With a stock cam, you will see the fuel pressure drop at least 6 to 8psi when you reconnect the vacuum line. Now your gauge is reading 35-38psi.

Tape the gauge to the windshield and take it out on the road - max load/max RPM the fuel system should be able to hold at least 40psi. Anything less than that is too low.

94CamaroZ28

I'm wondering about the catalytic converter, as well. Be interesting to see if it runs fine with the cat unbolted "for test purposes only". Yeah, it'll be loud, but if the symptoms don't occur with cat out of the equation, cat is clogged.

runlt1z28jake

To me it sounds like a torn or misproperly installed intake elbow. Possible vacum leak. Just my 13 cents. Rick

z71camaro

I didn't see the coil listed there. A weak spark will cause the exact same symptoms.