OK so this has probably been answered a million times on here but I'm new so PLEASE HELP ME!!! my 2002 malibu for the last several months has done this sort of 'chugging' thing when trying to speed up, didnt know what it was, then one day i go to leave for work, and it just will not turn over! had a back yard mechanic friend come look at it and he said it was the fuel pump, 250 bucks later, of course thats not the issue... crank sensor was replaced sept 2011. any ideas?!?!?!? PLEASE let me know!!! cant afford to play the guessing game with replacing what it "could" be

 

Check engine light on or flashing? Post the trouble codes if yes.

clogged cat? Does it rattle when you hammer fist it?
Remove the precat o2 sensor and let the exhaust bypass the cat. If it drives better this way the cat is restricted and needs replacing.

 

no engine light on. and hasnt ever even came on and gone off. no rattling either... should i still try what u said with the o2 sensor?

 

yes, remove the o2 from the exhaust and test drive.