LS1 Wont Start

Where to begin, two weeks ago i had the same problem as I do now. I checked the oil and cleaned the air filter. I didn't disconnect anything or unplug anything. I go to start it and the motor cranks, but does not start. I replugged in connectors around the intake, gave it a little throttle while starting it, checked fuses and tried several times to start it. But it would not start. After 20 minutes of trying, what "fixed it" was removing the pcv return to the intake, it started right up. I plugged in the pcv and not problems. That was two weeks ago and about 400 miles with no problems until last night.

Last night I go to start the car, and the same problem as before. It cranks, but doesn't start. I checked the fuses again, moved relays to different positions to see if the problem moves, unplugged the pcv again, released the pressure in the gas intake rails, checked plug wires, and still nothing.

What i can tell you is the fuel pump turns on, the starter works, the battery is good, fuses and relays good, good fuel that I know of, plugs replaced 3000 miles ago, other than routine maintenance nothing has been replaced swapped installed or moved in two years. My thoughts of what it could be are MAF or intake sensor problems or something with fuel.

Other than that, I have no idea and I need to get it home, any ideas or help is appreciated.

Have you scanned it for codes?

the car is still at work so i cant scan it yet. if i get it home i can scan it. im hoping i can get it home and pull a code to point me in a direction to go.

how meany coils do you have?

as long as the mas is plugged in it's not gonna be the mas throttle maybe mas no.
what kind of noise does it make?
Is the car stock??

If the MAF faults, the PCM ignores its signal and runs the engine in speed density. I do not believe the MAF is going to be your issue. Absent a weird VATS problem that is allowing the engine to crank, I would lean towards a crank position sensor or something of that nature.

Do you have ceramic spark plug boots stock from GM?

msd, plug wires, bolt ons except for cam and valve train, 8 coils, its not making any weird noises, everything sounds the same but it doesn't start after cranking. no exhaust noises or anything,

Could be low fuel pressure. What I would do is check the fuel pressure, check for spark, and check for fuel injector drive. One of those tests should point you in a direction.

Fuel pressure makes sense, but I pull the fuse for the fuel pump when I'm out of town in bad areas, and if I forget to put it bakc in before I start it, it will run for a split second. So, if it's holding pressure, it should fire, then die. What kind of mileage does it get? Are the plugs gapped wrong, and fouled? Did it get tuned after all the bolt ons? Maybe the same problem. It's running way rich, fouls immediately, won't fire. Wait a while, dries out. And giving it gas while cranking isn't helping.

i now thinking fuel pressure, im going to change the fuel filter, the old one has about 20000 miles on it. It has been tuned before with the bolts, years ago. The only thing that has been done to the car in the last 2 years is fluid changes, spark plugs and thats about it. nothing much.

Update, I went to work and it started right up, at each break it started up and when I got off of work it started. Tomorrow I will check for codes, but nothing popped up on the way home.