2004 Chevy Malibu will run but not rev up

SOURCE: 2004 optima wont stay running after fillup

semms to be like some of the vapor lines coming from thank to engine might be flooding your engine,
but also locate the fuel pressure regulator at the engine compartment and unplud the vacium hose, if you see any fuel coming out from fuel pressure regulator, or if the vacium hose smeel like fuel, then the regulator is not good.

SOURCE: Chevy Trailblazer 2003 ran the battery down now wont idle

try changing the air filter ,i had a problem ,at ilde in drive my trailblazer would stall, changed the air filter now it's not stalling and got my power back ,there is a secondary air pump that i have to change ,
not sure were it is ? still not running perfect but it's running better .and my service light is on too.
i got it put on scope ,it's the pump .
not sure if this helps ,but i'm start to run in to problems too,i have a 2004 trailblazer.
i like to do fix things myself ,i hope i can.it's the cost if you know what i mean.

SOURCE: 2004 chevy malibu won't start up

I have an 04 Malibu and when I get hard starts when I'm in the car I just press the accelerator down about half way and it always starts right up, some times I have to hold the accelerator down a little after starting to stop it from stalling but it is rare.

SOURCE: My 2004 BMW 325 ci convertible is difficult to start.

If the fuel filter has been replaced, then maybe these are other reasons:

1. intake camshaft sensor (known to go bad on BMW E46s). ~$100 part.

2. fuel injectors (though I doubt they go bad that easily). ~$100/ piece. Your car has 6.

3. Ignition coils. ~$90 a piece. Your car has 6.

4. mass air flow sensor. Again, another expensive part. ~$300.

SOURCE: On start up the engine starts fine and idles but wont rev up

try your maf sensor