Ok 03 cavalier second owner well mantained car 105k miles.
The last two days the car has ran just fine in the mornings, but at lunch
it refuses to start. Will run for 2 seconds one time and not again
till it wants to. Cranks over fine. Fuses all good relays good.
Not throwing any codes at all. Ran it hard after work yesterday
witg no issues. Any ideas crank sensor?

ok pulled all fuses again after work. car still did not start, untill 30 min or so later when i was ready to call the salvage yard. once again running just fine.... do believe i'm pulling my '80 out of the shop and dealing with the gas hog till i can find the issue. any help would be much appreciated.

I would at least change ur fuel filter and do a psi check on the schrader valve for proper fuel pressure.Even tho the car is only 8 yrs old the pump maybe going bad,or clogged filter.It might also be what u asked the crank position sensor,however I would def check the fuel psi first based on your info.The symptoms of a failing pump can do just what you said,however the crank sensor can cause it as well,same scenario.And the sensor going being intermittent will not set a code,it has to be a hard code to set the cel.Hope this helps unless I left something out may others add or correct me.

Fuel filter recently changed within 5000 miles ago. Got to find my adapters for my guages so I can test the fuel pressuer.