AVEO 2007 Engine start issue/problem

AVEO 2007 Engine start issue/problem
Sometimes when my AVEO 2007 will start and run with no issue.. but when i turn of the key it wont start again.. fuel pump pressure is good, i tried feeding a gasoline into the intake manifold, the engine starts a few seconds, I was thinking it might be an injector issue, i took out the fuel injector and tried to start the engine. I notice that it is not injecting, not even one of the four injecot is injecting fuel mist. no fuel mist comming out from the fuel injector...I replace the camshaft sensor still thesame issue. It will start and when turned off it wont start again, can anybody help me. Thanks

Did you check fuel pump relay by chance? Intermittent problems can be headaches but before going after the injectors Id just double check the system ahead of them. Fuel filter, fuel regulator, pump is slowly failing, relays/ fuses. Is the spark for sure ok? Nothing going on with the coil pack or plugs / wires? Just some suggestions to check off the list to try and focus on the root cause.

I did all your suggestion, I even replace the fuel pump. Fuel line pressire is strong... I dont suspect a problem with coil or spark plug... because when I tried to put some gasoline in the intake manifold and start the engine. It will crank and start for a while about a few seconds..

I have a new scenario discovered on the problem of my Aveo 2007. When the engine start the idling will gradually increase and I notice that when I remove the hose connected to the MAP sensor, it stabilizes and when I turn the engine off it will start immediately in one crank, but if it stays connected to the MAP it will not start. What could be the problem? Can anybody help me please resolve the issue. Thank

Faulty Sensor. Not to expensive or hard to change. They do go bad.

Thanks, I will try to replace the MAP sensor tomorrow

MAP Replaçeď, still thesàme problem. When i check the injector positive 12volt in present but when I crank the engine there is no negative pulse noted that is why the injectors were not spraying fuel... can the TPS cause the problem? I already replaced the camshaft and crackshaft, I dont know what to check next. Please any help. Thanks and Thank you Urilken

My apologize for having you waste time on something un-necessary. I'm curious as to if your check engine light is on or even if its not if you have checked for codes?
How's the electrical grounds for the engine and fuel tank, etc.?

do the exact thing when i got problem