I think I know what the problem is with the last few complaints I've read in here! I'm having the same problem with it beginning to not start sometimes, to all of the sudden running very, very badly one day for no particular reason. I took my 2000 Alero 3.4L to AutoZone for a free diagnostic and just as I suspected... the Mass Airflow Sensor is bad! My "Service Engine" light as well as the "Security" light has always stayed on even before this. However, now the "Service Engine" light blinks on/off all the time.

Please listen everyone out there! A bad MAF sensor will make you think the damn car is falling apart when you drive it! It will surge, buck, misfire, and all the works when the MAF goes bad. I've had a few different vehicles do this to me. I even replaced the MAF on a Nissan Maxima I had once and cost $184 for only the part... it went bad 3 months later and I had to replace it again but it was under warranty fortunately! The Mass Airflow Sensor for my 2000 is around $82 at AutoZone and anyone should be able to replace this part yourself with little effort. I hope this helps a lot of you out there. My Alero runs great and gets good gas mileage when it's running proper.

I TOOK MY CAR ON DEC 16TH FOR A TUNE-UP BECAUSE IT WAS DRIVING LIKE SH*T. AS A COURTESY THE MECHANIC PUT THE CAR ON THE COMPUTER TO TELL ME THAT THERE WAS #4 PISTON MISFIRE IN THE ENGINE. I DIDN'T KNOW WHAT THE HELL THAT WAS. I'M BEING ADVISED THAT IF I WANT TO KEEP THE CAR AND GET IT FIXED REPLACED THE PISTON AND BE PREPARED FOR THE NEXT THING TO GO WRONG OR REPLACE THE ENGINE ALTOGETHER. I'M NOT DONE PAYING MY CAR OFF TO BE OUT OF THIS KIND OF MONEY AND IT'S JUST SITTING. GM OWES ME SOME MONEY!!!! DOES ANYBODY KNOW WHO WE NEED TO TALK TO RECOUP OUR LOSES OF THE MONIES SPENT TO KEEP THIS CAR RUNNING?