Hello,
I have a 2004 Chevy Monte Carlo SS. I've had this car for a few months and have begun to have issues with it shutting off at random times or simply not starting at all. Whenever it doesn't start it will crank but the engine won't fire up. Sometimes disconnecting and reconnecting the battery works but otherwise I have no idea what could be causing this. I replaced the battery when I initially got it, tested the alternator and it came back good, cleaned the MAF sensor and replaced the camshaft sensor. So far, none of this has helped. There is no check engine light whenever it shuts off/doesn't start and does not shoot any codes. I took it somewhere but they were unable to find anything that was glaringly obvious and they did no actual work to it and it worked after that up until the day that I'm posting on this thread. I'm at the point where I've done all I can do and I need extra guidance. I'm still fairly new to car stuff and I can only do so much. I've read about the fuel pump and I can hear it hum whenever it starts and the fuel pump has already got replaced in this car before. Any help or commentary is appreciated! Thank you

 

Cleaning the MAF doesn't fix the problem sometimes... Try unplugging it and see if it starts. Other possible culprits include the ignition module and crank sensor.

 

It sounds like you need to take it somewhere more reputable... Might have to pay for an hour or labor for them to diagnose but that will find the issue.

 

I'm with nitehawk, MAF sounds like a really strong candidate (especially dying out of nowhere).

Do you have access to a scan tool? If not, the method he suggested is a good alternate (just unplug it). Itll throw a code, but don't worry about that - just see if it dies anymore or not. The car will default to running off the MAP sensor and will run 100% fine with the maf unplugged if its the issue.

Even if thats not it, you've at least crossed one item off the possibility list.

I do agree also that cleaning it doesnt help with this issue. Ive only seen cleaning help on cars with an over oiled aftermarket air filter (and the problem they experience is different from yours - they run like garbage all the time because the maf is coated in garbage).